Systems and methods for operating analyte sensor electronics - Patents.com

Abstract

To provide systems and methods for activating analyte sensor electronics.SOLUTION: Various analyte sensor systems for controlling activation of analyte sensor electronic circuitry are provided. Related methods for controlling analyte sensor electronic circuitry are also provided. Various analyte sensor systems for monitoring an analyte in a host are also provided. Various circuits for controlling activation of an analyte sensor system are also provided. Analyte sensor systems utilizing a state machine having a plurality of states for collecting a plurality of digital counts and waking a controller in response to a wake-up signal are also provided. Related methods for such analyte sensor systems are also provided. Systems for controlling activation of analyte sensor electronic circuitry utilizing a magnetic sensor are further provided. One or more display devices configured to display one or more analyte concentration values are also provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] INCORPORATION BY REFERENCE TO RELATED APPLICATIONS Any and all priority claims identified in the Application Data Sheet, or any amendments thereto, are incorporated herein by reference under 37 CFR 1.57. This application claims the benefit of U.S. Provisional Application No. 62 / 666,554, filed May 3, 2018. The aforementioned applications are incorporated herein by reference in their entireties and expressly made a part hereof.

[0002] The present development relates generally to medical devices such as analyte sensors, and more particularly, but not by way of limitation, to systems, devices and methods relating to operating analyte sensor electronics on such medical devices. [Background technology]

[0003] Diabetes mellitus is a disease in which the pancreas cannot make enough insulin (type I or insulin-dependent) and / or insulin is not effective (type 2 or non-insulin-dependent). In the diabetic state, the victim suffers from hyperglycemia, which causes many physiological disorders associated with microvascular deterioration, such as kidney failure, skin ulcers, or bleeding into the vitreous humor of the eye. Hypoglycemic reactions (low blood sugar) can be induced by inadvertent overdosing of insulin or after normal administration of insulin or glucose-lowering drugs accompanied by abnormal exercise or inadequate food intake.

[0004] Traditionally, people with diabetes carry a self-monitoring blood glucose (SMBG) monitor, which can require an uncomfortable finger-prick method. Due to lack of comfort and convenience, diabetics typically only measure their glucose levels two to four times per day. Unfortunately, these time intervals are so far apart that diabetics may be alerted too late to a hyperglycemic or hypoglycemic condition, which can result in dangerous side effects. In fact, not only are diabetics unlikely to obtain SMBG readings in a timely manner, but the limitations of traditional methods mean that they do not know whether their blood glucose levels are rising (getting higher) or falling (getting lower).

[0005] As a result, a variety of non-invasive, transdermal (e.g., transcutaneous) and / or implantable electrochemical sensors have been developed to continuously detect and / or quantify blood glucose levels. These devices generally transmit raw or minimally processed data for subsequent analysis at a remote device, which may include a display. The transmission to a wireless display device may be wireless. The remote device may then provide the user with information regarding the user's blood glucose level. Systems using such implantable sensors may provide the user with more up-to-date information and therefore reduce the risk that the user will fail to regulate the user's blood glucose level. Nevertheless, such systems still typically rely on the user to take action to regulate the user's blood glucose level, for example by administering an injection.

[0006] Such systems may typically include an embeddable glucose sensor in a host and sensor electronics for processing and communicating glucose-related information. However, in such systems, the sensor and sensor electronics are typically designed to be connected by a user or host only after the sensor is implanted in the user. As a result, a pre-connected system may potentially reduce the amount of user interaction associated with deploying an analyte sensor system.

[0007] This Background is provided to introduce a brief context for the Summary and Detailed Description that follow. This Background is not intended to aid in determining the scope of the claimed subject matter, nor is it to be considered as limiting the claimed subject matter to implementations that solve any and all of the disadvantages or problems discussed above. Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above characteristics associated with some systems, a need exists for an analyte sensor system configured such that the analyte sensor and the analyte sensor electronics are electrically and mechanically coupled to one another before the analyte sensor is implanted in a user or host. The present disclosure generally relates to controlling operation of sensor electronics for wireless communication of analyte data collected using an analyte sensor system. More specifically, the present disclosure is directed to systems, methods, apparatus, and devices for using a number of techniques for controlling such operation in an analyte sensor system in which the analyte sensor is both electrically and mechanically connected to the analyte sensor electronics before being implanted in a host. [Means for solving the problem]

[0009] There are numerous advantages associated with the systems, methods, devices, and other aspects and embodiments of the present disclosure. For example, an analyte sensor system configured for an analyte sensor to be connected to the analyte sensor electronics prior to implantation may not require significant user interaction, may be smaller, simpler, more elegant, and / or less expensive, and may have fewer sealing, deployment, and connection issues. For example, problems with connecting, aligning, retaining, and separating the analyte sensor associated with connecting the analyte sensor during transcutaneous implantation may be avoided. As a further example, in a system that is not designed to be pre-connected, a seal may need to be created between the analyte sensor electronics and the analyte sensor and / or their housing when the analyte sensor and analyte sensor electronics are mated in the field. However, in a pre-connected system, this seal may be accomplished during system manufacturing. Thus, failures that may occur as a result of the insertion of the analyte sensor may be avoided. Another exemplary advantage of a pre-connected system is that it may be advantageous for the analyte sensor system to transition to an active state in order to capture analyte measurements close to the time the analyte sensor is implanted in the user. This allows the analyte processing algorithms to more accurately estimate the sensor implantation time, and therefore more accurately process the analyte values ​​of the sensor signal.

[0010] There may also be some challenges associated with implementing a pre-connected analyte sensor system. For example, in a non-pre-connected system, monitoring the analyte sensor electronics for an electrical signal indicating the presence of an analyte sensor in the circuit may be used to activate the analyte sensor system. However, in a pre-connected system, such a signal may be subject to noise and may lead to false triggering / activation of the system. Additionally, monitoring the analyte sensor prior to implantation may cause undesirable changes in the analyte sensor (e.g., deviation from a calibration value). Thus, monitoring the analyte sensor electronics solely for the analyte sensor signal may not be well suited as a primary or sole means for activation purposes in certain cases.

[0011] Thus, alternative and / or additional means of activating the analyte sensor system may be used. However, such means should be robust against false wake-up events, maintain accurate analyte sensor calibration, not consume large amounts of power, and allow for sufficiently rapid wake-up of the analyte sensor system. In addition, a pre-connected system should provide an improved user experience, for example, by reducing and / or eliminating user steps associated with connection and / or reducing and / or eliminating the possibility of pairing incompatible sensors and electronics. Further, for example, pre-connected systems and solutions may facilitate faster initiation of connection (e.g., wireless connection) in closed-loop systems (e.g., automated insulin delivery systems, and related or similar systems and applications) that may lead to reduced missing analyte data. Also, the time associated with setting up such a system (including, for example, the time to implant a sensor in a user's body and / or to activate or establish operation of the analyte sensor electronics) may be substantially reduced, such as in a healthcare provider scenario (e.g., a doctor's or other clinic).

[0012] The embodiments of the present disclosure overcome these challenges and provide the advantages discussed above by using multiple methods of detecting and verifying the conditions for activating the analyte sensor electronics. By using one or more validation methods, the embodiments of the present disclosure provide a system that is more robust against false wake-ups, thus saving power and providing better overall reliability, as well as providing other advantages discussed above. According to the embodiments of the present disclosure, multiple indicators of analyte sensor insertion can be used to trigger the analyte sensor electronics to exit a lower power state in order to implement a robust wake-up or activation procedure and to avoid false wake-up events. In many embodiments, the system is designed to largely avoid altering the characteristics of the analyte sensor, to be robust against signal noise that may be experienced prior to analyte sensor implantation (e.g., which may result from humidity, temperature, vibration, etc.), and to operate in a manner suitable for low power, battery-powered devices.

[0013] With regard to the numerous techniques that may be used to detect an actuation event of an analyte sensor electronic circuit, such techniques may generally be divided into those that utilize primary signals and those that utilize secondary signals. As referred to herein, a primary signal may generally relate to a signal that is related to, correlates with, is derived from, characterizes, and / or describes analyte information obtained from a host using the analyte sensor. As referred to herein, a secondary signal may generally relate to information collected using the analyte sensor system, the collected information being information other than the primary signal(s) (e.g., the collected information is not information used in a primary signal capacity to describe the relationship between the signal and the analyte information). The secondary signal or information may be collected using the analyte sensor (e.g., one or more electrodes) and / or other means. Such other means may include circuitry or components internal to the analyte sensor system or external to the analyte sensor system, as described in further detail herein. Additionally, secondary signals or information may be collected using the analyte sensor system and / or external components, alone or in conjunction with user interaction.

[0014] Combining multiple techniques that may be used to detect activation events of the electronic circuitry of an analyte sensor can increase the robustness of the system against false wake-ups, for example, one technique may be used to check another technique that may be subject to noise or false triggering, for example, one or more primary signals may be used to check one or more secondary signals. In some cases, a primary signal (e.g., an analyte value or signal that may be representative thereof, such as a voltage, current, count, or other signal) may be used in combination with a secondary signal that may be collected / derived using the analyte sensor signal (e.g., impedance, capacitance, etc. of the analyte sensor). In some cases, a primary signal may be used in combination with one or more secondary signals that are not derived / collected using means other than or in addition to the analyte sensor. In embodiments, the primary signal information may be combined with secondary signal information, which may be or include one or more non-analyte sensor signals or information. In embodiments, an analyte sensor system may use primary signal(s) and / or secondary signal(s) collected / derived using an analyte sensor, and information collected / derived using means other than the analyte sensor (e.g., accelerometer signals or other techniques, as described herein), and compare the foregoing over one or more time periods for purposes of actuating the analyte sensor system. In this manner, embodiments of the present disclosure may more accurately assess actuation time and / or better avoid and / or reduce false wake-ups in a pre-connected analyte sensor system, while maintaining battery-efficient, lower power modes and robust sensor performance.

[0015] A first aspect of the disclosure includes a system for controlling operation of an analyte sensor electronics. The system includes an analyte sensor electrically and mechanically coupled to the analyte sensor electronics prior to transitioning the system to an operational state. The analyte sensor electronics is adapted to perform several operations. One such operation is to trigger an indication for the system to exit a lower power state and transition to an operational state. The indication is triggered based on a threshold associated with deployment of the system. Another such operation is to generate a control signal in response to the indication, operable to cause the analyte sensor to collect information related to a level of an analyte in a host. Yet another such operation is to generate a comparison between the information related to a level of an analyte in a host and a condition. The system exits the lower power state and transitions to an operational mode based on the indication being triggered and the comparison indicating that the level of an analyte in the host satisfies the condition.

[0016] In a particular implementation of the first aspect, which may be generally applicable but also particularly applicable in relation to any other implementation of the first aspect, the analyte sensor electronics is further adapted to cause the system to trigger an indication in response to the threshold being satisfied for at least a predetermined time.

[0017] In a particular implementation of the first aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the first aspect, the indication is a signal generated using one or more of an actuation detection circuit and an actuation detection component adapted to detect one or more of insertion of the analyte sensor into the host and deployment of the system.

[0018] In a particular implementation of the first aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the first aspect, the control signal is a signal operable to cause the potentiostat to apply a voltage bias to the analyte sensor, thereby causing the analyte sensor to collect information related to the level of the analyte in the host.

[0019] In a particular implementation of the first aspect, which may be generally applicable but also particularly applicable in relation to any other implementation of the first aspect, after the system transitions to an operational state, the system continues to collect information related to the level of the analyte in the host and communicates the information to one or more display devices or one or more partner devices.

[0020] In certain implementations of the first aspect, which may be generally applicable but are also particularly applicable in relation to any other implementations of the first aspect, the threshold value is typically related to a level of a known analyte present in the human host.

[0021] In a particular implementation of the first aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the first aspect, the indication is generated using one or more of: (1) a detected proximity between the analyte sensor electronics and a reference object; (2) a temperature monitored using the analyte sensor electronics; (3) an output of an accelerometer of the analyte sensor electronics; (4) a response generated using wireless signaling transmitted or received by the analyte sensor electronics; (5) a detected change in air pressure measured by the analyte sensor electronics; (6) audio information monitored by the analyte sensor electronics; (7) a signal generated by the analyte sensor electronics in response to photons detected by the analyte sensor electronics; (8) a conductivity measured between two terminals of the analyte sensor electronics; (9) a mechanical switch located on or within a housing of the analyte sensor electronics; (10) a component adapted to change a connection between two conductive elements of the analyte sensor electronics in response to movement of the component; and (11) a measured strain.

[0022] In a particular implementation of the first aspect, which may be generally applicable but also particularly applicable in relation to any other implementation of the first aspect, the system exits the lower power state based on a determination that the level of the analyte in the host exceeds a threshold value.

[0023] In a particular implementation of the first aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the first aspect, the analyte sensor electronics is further adapted to cause the system to trigger an indication in response to a programmed time period condition being satisfied.

[0024] In a particular implementation of the first aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the first aspect, information related to the level of the analyte in the host is used to generate the detected count. Further, the condition includes a threshold characteristic of the count. If the comparison indicates that the detected count has reached the threshold, the system exits the lower power state and transitions to the operational mode.

[0025] A second aspect of the disclosure includes a method for controlling an analyte sensor electronics. The method includes the analyte sensor electronics acquiring a first signal generated using one or more of the analyte sensor and the secondary sensor. The method includes determining whether a first condition is achieved based on the first signal acquired by the analyte sensor electronics. The method also includes the analyte sensor electronics activating an analyte measurement circuit in response to the first condition being achieved. In addition, the method includes the analyte measurement circuit collecting information related to an analyte value in a host using the analyte sensor. The analyte sensor was coupled to the analyte sensor electronics before the analyte sensor was implanted in the host. The method also includes the analyte sensor electronics determining whether the information related to the analyte value in the host achieves a second condition.

[0026] Additionally, the method according to the second aspect includes, in response to the analyte sensor electronics determining that the information related to the analyte value in the host achieves the second condition, the sensor electronics exiting the lower power consumption mode. Alternatively, the method includes, in response to the analyte sensor electronics determining that the information related to the analyte value in the host does not achieve the second condition, the analyte sensor electronics remaining in the lower power consumption mode and obtaining a second electrical signal indicative of whether the first condition is achieved.

[0027] In a particular implementation of the second aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the second aspect, the second condition is achieved when the information related to the analyte value indicates that the level of the analyte value in the host meets a threshold value.

[0028] In a particular implementation of the second aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the second aspect, the first condition represents the proximity of the analyte electronic circuit to a reference point.

[0029] In a particular implementation of the second aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the second aspect, the first condition represents a level of acceleration detected using an accelerometer.

[0030] In a particular implementation of the second aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the second aspect, the first condition relates to one or more electrical characteristics measured of the acceleration sensor.

[0031] A third aspect of the present disclosure includes a system for monitoring an analyte in a host. The system includes an analyte sensor. The analyte sensor includes one or more electrodes adapted to collect information related to a level of the analyte in the host. The system also includes sensor electronics mechanically and electrically coupled to the analyte sensor before the analyte sensor is implanted in the host. The sensor electronics is adapted to generate a secondary indicator using a first condition and a measurement of an electrical signal passing between at least two of the one or more electrodes. The sensor electronics is further adapted to cause the system to transition to an active state in response to the sensor electronics generating a confirmation of the secondary indicator using the second condition and the information related to the level of the analyte in the host.

[0032] In a particular implementation of the third aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the third aspect, the sensor electronics is further adapted to determine one or more of an impedance, a capacitance, a voltage, and a current associated with the one or more electrodes using measurements of an electrical signal passing between at least two of the one or more electrodes.

[0033] A fourth aspect of the present disclosure includes a system for monitoring an analyte in a host. The system includes analyte sensor electronics. The system further includes an analyte sensor, the analyte sensor being mechanically and electrically coupled to the analyte sensor electronics before the analyte sensor is implanted in the host. In addition, the system includes an actuation detection circuit coupled to the analyte sensor. The actuation detection circuit is adapted to generate a control signal operable to cause the analyte sensor to obtain information related to a level of the analyte in the host. The control signal is generated in response to an electrical signal indicating that a first condition is met. The analyte sensor electronics is adapted to cause the system to change state if the level of the analyte in the host meets a second condition and if the electrical signal indicates that the first condition is met.

[0034] In certain implementations of the fourth aspect, which may be generally applicable but are also particularly applicable in relation to any other implementations of the fourth aspect, the indication that the first condition is met is generated using one or more of the parameters, inputs, and / or variables. For example, any of the following may be used, alone or in combination, to generate the indication: The indication may be generated using a detected proximity between the analyte sensor electronics and a reference object. The indication may be generated using a temperature monitored by the analyte sensor electronics. The indication may be generated using an output of an accelerometer of the analyte sensor electronics. In an embodiment, the indication may be generated using a response generated using wireless signaling transmitted or received by the analyte sensor electronics. Additionally, the indication may be generated using a detected change in air pressure measured by the analyte sensor electronics. The indication may also be generated using audio information, which may be monitored by the analyte sensor electronics. Additionally, the indication may be generated using a signal generated by the analyte sensor electronics in response to photons detected by the analyte sensor electronics. An indication may also be generated using the conductivity measured between two terminals of the analyte sensor electronics. In some cases, the indication may be generated using a mechanical switch located on or within the housing of the analyte sensor electronics. In embodiments, the indication may be generated using a component adapted to change a connection between two conductive elements of the analyte sensor electronics in response to movement of the component. The indication may be generated using the measured strain.

[0035] A fifth aspect of the present disclosure includes a system for monitoring an analyte in a host. The system includes an analyte sensor electronic circuit. The system further includes an analyte sensor adapted to be coupled to the analyte sensor electronic circuit before the analyte sensor is implanted in the host. Additionally, the system includes an actuation detection circuit coupled to the analyte sensor. The actuation detection circuit is coupled to the analyte sensor and adapted to monitor the secondary sensor according to a sampling frequency and to increase the sampling frequency in response to a first event detected using the secondary sensor. The actuation detection circuit is further adapted to monitor the secondary sensor according to the increased sampling frequency and to generate a control signal in response to detecting a second event. The control signal is operable to cause the analyte sensor to perform a measurement to obtain information indicative of a level of the analyte in the host once the analyte sensor is implanted in the host. The analyte sensor electronic circuit is further adapted to cause the system to change state in response to the information indicative of the level of the analyte in the host satisfying a condition and further in response to the actuation detection circuit detecting a second event.

[0036] In a particular implementation of the fifth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the fifth aspect, the sampling frequency is set according to one or more classifications of the first event and the second event determined by the actuation detection component.

[0037] A sixth aspect of the present disclosure includes a circuit for controlling operation of an analyte sensor system. The circuit includes a detection circuit adapted to indicate whether a signal at an input terminal of the detection circuit achieves a condition. The detection circuit is further adapted to trigger the analyte system to exit a lower power state when the detection circuit indicates that the signal achieves the condition. The circuit also includes a first switch element adapted to control a coupling between the input terminal of the detection circuit and a first terminal of the analyte sensor. The analyte sensor is adapted to collect information related to an analyte level in the host. The circuit further includes a second switch element adapted to control a coupling between the first terminal of the analyte sensor and a first terminal of a potentiostat. The potentiostat is adapted to apply a voltage bias to the analyte sensor that causes the analyte sensor to collect information related to an analyte level in the host. The input terminal of the detection circuit is coupled to a second terminal of the analyte sensor and to a second terminal of the potentiostat. The circuitry is adapted to generate an additional detectable event to operate the analyte sensor system, including by causing the second switch element to couple the first terminal of the analyte sensor to the first terminal of the potentiostat and the first switch element to decouple the input terminal of the detection circuit from the first terminal of the analyte sensor at a first time point, and at a second time point, the circuitry is adapted to cause the second switch element to decouple the first terminal of the analyte sensor from the first terminal of the potentiostat and the first switch element to couple the input terminal of the detection circuit to the first terminal of the analyte sensor.

[0038] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the circuit also includes a capacitive element coupled between the input terminal of the detection circuit and a second reference voltage.

[0039] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the second switch element is adapted to couple the input terminal of the detection circuit to the first terminal via the resistive element.

[0040] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the circuit further includes a third switch element adapted to couple the input terminal of the detection circuit to a second reference voltage.

[0041] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, when the third switch element couples the input terminal of the detection circuit to the second reference voltage, the capacitive element discharges.

[0042] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, a terminal of the third switch element is coupled to a clock that causes the third switch element to periodically couple an input terminal of the detection circuit to the second reference voltage.

[0043] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the first switch element is driven by a common signal and the second switch element is driven by an inverted version of the common signal.

[0044] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the first switch element and the second switch element are driven by a common signal and have opposite polarities.

[0045] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the voltage at the input terminal of the detection circuit is indicative of a current between a first terminal of the analyte sensor and a second terminal of the analyte sensor when the analyte sensor is implanted in a host.

[0046] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, a reference terminal of the detection circuit is coupled to a first reference voltage. The detection circuit includes a comparator.

[0047] In a particular implementation of the sixth aspect, which may be generally applicable but is also particularly applicable in relation to any other implementation of the sixth aspect, the second voltage reference is ground.

[0048] In some embodiments, an analyte sensor system is provided. The analyte sensor system includes an analyte sensor. The analyte sensor system includes a state machine configured to cause a first potential to be applied across the analyte sensor during a first sampling state and a second potential to be applied across the analyte sensor during a second sampling state. The analyte sensor system includes an analyte sensor measurement circuit configured to generate a first digital count corresponding to a first current through the analyte sensor during the first sampling state based on application of the first potential, and to generate a second digital count corresponding to a second current through the analyte sensor during the second sampling state based on application of the second potential. The analyte sensor system includes a detection circuit configured to determine a first difference between the second digital count and the first digital count, and to generate a controller wake-up signal in response to at least the first difference satisfying a threshold value. The analyte sensor system includes a controller configured to enter a lower power state for at least a duration of the first sampling state, the second sampling state, and the determination of the first differential, and to transition from the lower power state to an operating state in response to a controller wake-up signal. The controller is configured to determine an impedance of the analyte sensor based at least in part on the first differential.

[0049] In some embodiments, the state machine is configured to cause initiation of a first potential applied across the analyte sensor during a first delay state immediately preceding the first sample state, and the analyte sensor measurement circuit is configured to suspend generation of the digital count during the first delay state.

[0050] In some embodiments, the state machine is configured to cause initiation of a second potential applied across the analyte sensor during a second delay state immediately preceding the second sample state, and the analyte sensor circuit is configured to cease generating the digital count during the second delay state.

[0051] In some embodiments, the state machine is configured to cause a zero potential to be applied across the analyte sensor during a third delay state following the second sampling state, and the analyte sensor measurement circuit is configured to cease generating the digital count during the third delay state.

[0052] In some embodiments, the detection circuit includes a first sample buffer configured to store the first digital count, hi some embodiments, the detection circuit includes a differentiator configured to receive the first digital count from the first sample buffer and the second digital count from the analyte sensor measurement circuit and determine a first difference.

[0053] In some embodiments, the detection circuit includes an integrator configured to generate a sum of the first difference and a second difference between at least the third digital count and the fourth digital count. The third digital count corresponds to a third current through the analyte sensor during a subsequent stage of the first sampling state, and the fourth digital count corresponds to a fourth current through the analyte sensor during a subsequent stage of the second sampling state. In some embodiments, the detection circuit is configured to generate a controller wake-up signal in response to the sum of at least the first difference and the second difference satisfying a threshold value.

[0054] In some embodiments, the controller is configured to define at least one parameter of the state machine before transitioning to a lower power state. In some embodiments, in a first mode of operation of the analyte sensor system, the first potential is zero volts and the second potential is a predetermined amount greater than the first potential, and in a second mode of operation of the analyte sensor system, the first potential is the same as a potential applied across the analyte sensor to determine an analyte concentration in the host and the second potential is a predetermined amount greater than the first potential.

[0055] In some embodiments, a method for controlling an analyte sensor system is provided. The method includes utilizing a state machine to cause a first potential to be applied across the analyte sensor during a first sampling state and a second potential to be applied across the analyte sensor during a second sampling state. The method includes utilizing an analyte sensor measurement circuit to generate a first digital count corresponding to a first current through the analyte sensor during the first sampling state based on the application of the first potential and a second digital count corresponding to a second current through the analyte sensor during the second sampling state based on the application of the second potential. The method includes utilizing a detection circuit to determine a first difference between the second digital count and the first digital count and generating a controller wake-up signal in response to at least the first difference satisfying a threshold value. The method includes causing the controller to transition to a lower power state for at least a duration of the first sampling state, the second sampling state, and determining the first difference, transition from the lower power state to an operating state in response to a controller wake-up signal, and determine impedance of the analyte sensor based at least in part on the first difference.

[0056] In some embodiments, the method includes commencing application of a first potential across the analyte sensor during a first delay state immediately preceding the first sample state, and discontinuing generation of a digital count by the analyte sensor measurement circuitry during the first delay state.

[0057] In some embodiments, the method includes commencing application of a second potential across the analyte sensor during a second delay state immediately preceding the second sample state, and discontinuing generation of a digital count by the analyte sensor measurement circuitry during the second delay state.

[0058] In some embodiments, the method includes utilizing a state machine to cause a zero potential to be applied across the analyte sensor during a third delay state following the second sample state, and interrupting generation of a digital count by the analyte sensor measurement circuitry during the third delay state.

[0059] In some embodiments, the method includes storing the first digital count in a first sample buffer prior to determining the first difference. In some embodiments, the method includes receiving the first digital count from the first sample buffer by a differentiator, receiving the second digital count from the analyte sensor measurement circuit by the differentiator, and determining the first difference utilizing the differentiator.

[0060] In some embodiments, the method includes utilizing an integrator to generate a sum of the first difference and a second difference between at least a third digital count and a fourth digital count, where the third digital count corresponds to a third current flowing through the analyte sensor during a subsequent stage of the first sampling state, and the fourth digital count corresponds to a fourth current flowing through the analyte sensor during a subsequent stage of the second sampling state.

[0061] In some embodiments, the method includes generating a controller wake-up signal in response to at least the sum of the first difference and the second difference satisfying a threshold value.

[0062] In some embodiments, the method includes utilizing the controller to define at least one parameter of the state machine prior to transitioning to a lower power state.

[0063] In some embodiments, in a first mode of operation of the analyte sensor system, the first potential is zero volts and the second potential is a predetermined amount greater than the first potential, and in a second mode of operation of the analyte sensor system, the first potential is the same as a potential applied across the analyte sensor to determine an analyte concentration in the host and the second potential is a predetermined amount greater than the first potential.

[0064] In some embodiments, a system for controlling operation of an analyte sensor electronics is provided that includes an analyte sensor, a magnetic sensor configured to trigger a wake signal in response to a magnet being brought sufficiently close to the magnetic sensor, and the analyte sensor electronics configured to exit a lower power state and transition to an operating state in response to the wake signal, and to receive an indication of one or more analyte concentration values ​​from the analyte sensor in response to transitioning to the operating state.

[0065] In some embodiments, the magnet is disposed on a display device configured to display one or more analyte concentration values. In some embodiments, the magnetic sensor is configured to trigger a wake signal in response to the magnet being moved in at least one of a predetermined motion and a predetermined spatial orientation relative to the magnetic sensor.

[0066] In some embodiments, a display device configured to display one or more analyte concentration values ​​is provided. The display device includes a microphone configured to generate one or more audio waveforms of sounds emitted by the applicator while deploying the analyte sensor system. The display device includes a processor configured to execute an application while the applicator deploys the analyte sensor system. The application is configured to analyze the one or more audio waveforms and identify one of a successful deployment and an unsuccessful deployment of the analyte sensor system based on analyzing the one or more audio waveforms. The display device includes a display configured to display at least one of a first indication of a successful deployment in response to the application identifying a successful deployment and a second indication of an unsuccessful deployment in response to the application identifying an unsuccessful deployment.

[0067] In some embodiments, analyzing the one or more audio waveforms includes identifying at least a portion of the one or more audio waveforms that indicates at least a portion of the applicator performing a known movement of successful deployment.

[0068] This Summary is intended to provide an overview of the subject matter of this patent application. It is not intended to provide an exclusive or exhaustive description of the disclosure. The Detailed Description is included to provide further information regarding this patent application. Other aspects of the present disclosure will be apparent to those of ordinary skill in the art upon reading and understanding the following Detailed Description and viewing the Drawings that form a part hereof, each of which should not be construed in a limiting sense. [Brief description of the drawings]

[0069] Further aspects of the present disclosure will be more readily understood by considering the following detailed description of the various disclosed embodiments in conjunction with the accompanying drawings.

[0070] [Figure 1] 1 illustrates aspects of an example system that may be used in connection with some embodiments. [Diagram 2] 1 illustrates aspects of an example system that may be used in connection with some embodiments. [Figure 3A] 1 is an exemplary analyte sensor system, according to some embodiments. [Figure 3B] 1 is an exemplary analyte sensor system, according to some embodiments. [Figure 4] 1 illustrates aspects of an exemplary analyte sensor system, according to some embodiments. [Diagram 5] 1 illustrates aspects of an exemplary analyte sensor system, according to some embodiments. [Figure 6A] 1 illustrates aspects of an exemplary application device, according to some embodiments. [Figure 6B] 1 illustrates another diagram of an exemplary application device, according to some embodiments. [Figure 6C] 1 illustrates aspects of an exemplary actuation detection component, according to some embodiments. [Figure 6D] 1 illustrates aspects of a top view of an exemplary connector, according to some embodiments. [Figure 6E] 1 illustrates aspects of a top view of another exemplary connector, according to some embodiments. [Figure 7A] 1 shows an exemplary circuit diagram of an analyte sensor according to some embodiments. [Figure 7B] 1 shows an exemplary plot of analyte sensor impedance as a function of time according to some embodiments. [Figure 7C] 1 shows an exemplary plot of analyte sensor impedance as a function of time according to some embodiments. [Figure 8A] 1 illustrates aspects of an exemplary actuation detection circuit, according to some embodiments. [Figure 8B] 1 shows an exemplary plot of an analyte sensor signal according to some embodiments. [Figure 8C] FIG. 1 is an operational flow diagram illustrating various operations that may be performed according to some embodiments. [Figure 9]1 illustrates an example plot showing the operation of an example analyte sensor system, according to some embodiments. [Figure 10] FIG. 1 is an operational flow diagram illustrating various operations that may be performed according to some embodiments. [Figure 11] 1 illustrates an exemplary computing module, according to some embodiments. [Figure 12] 13 illustrates a timing diagram associated with a state machine for ultimately determining the impedance of an analyte sensor, according to some embodiments. [Figure 13] 1 illustrates a state diagram associated with a state machine for ultimately determining the impedance of an analyte sensor, according to some embodiments. [Figure 14] FIG. 1 illustrates a functional block diagram associated with a state machine for ultimately determining the impedance of an analyte sensor, according to some embodiments. [Figure 15] 1 shows a flowchart of a method for controlling an analyte sensor system according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] The drawings are described in more detail in the following description and examples and are provided for illustrative purposes only, merely depicting typical or exemplary embodiments of the present disclosure. The drawings are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. It should also be understood that the present disclosure may be practiced with modification or alteration, and that the present disclosure may be limited only by the claims and their equivalents.

[0072] Embodiments of the present disclosure are directed to systems, methods, and devices for wireless communication of analyte data. In various deployments described herein, the analyte data is glucose data generated by an analyte sensor system configured to connect to a display device, a partner device (e.g., a medical device such as an insulin pump), other remotely connectable devices, and the like. Implementing aspects of the present disclosure, including the systems, methods, apparatus, and devices described herein, more specifically providing increased robustness against failures or otherwise undesired activation, wake-up, and / or associated mode or state changes, and the like, to components of the analyte sensor system, may improve the accuracy, robustness, and / or power management of an analyte sensor system that wirelessly communicates with a display device, one or more partner devices, and / or other (e.g., electronic) devices. Additionally, implementing aspects of the present disclosure may also enable improved performance in terms of lifetime and usability of the analyte sensor system.

[0073] Details of several exemplary embodiments of the systems, methods, and devices of the present disclosure are described in this description, and in some cases elsewhere in the disclosure. Other features, objects, and advantages of the present disclosure will become apparent to those skilled in the art upon review of the disclosure, description, drawings, examples, and claims. All such additional systems, methods, devices, features, and advantages are intended to be included (expressly or by reference) in this description, be within the scope of the present disclosure, and be protected by one or more of the accompanying claims.

[0074] System Overview and Example Configurations 1 illustrates a system 100 that may be used in connection with embodiments of the present disclosure that involve collecting, monitoring, and / or providing information regarding analyte levels present in a user's body, including, for example, the user's blood glucose level. System 100 illustrates aspects of an analyte sensor system 8 that may be communicatively coupled to display devices 110, 120, 130, and 140, a partner device 136, and / or a server system 134.

[0075] The analyte sensor system 8 in the illustrated embodiment includes a sensor electronics module 12 and an analyte sensor 10 associated with the sensor electronics module 12. The analyte sensor electronics module 12 may be electrically and mechanically coupled to the analyte sensor 10 before the analyte sensor 10 is implanted in a user or host. Thus, the analyte sensor 10 may not require a user to couple the analyte sensor electronics module 12 to the analyte sensor 10. For example, the analyte sensor electronics module 12 may be physically / mechanically and electrically coupled to the analyte sensor 10 during manufacturing, and this physical / mechanical and electrical connection may be maintained during shipping, storage, insertion, use, and removal of the analyte sensor system 8. Thus, the electromechanically connected components of the analyte sensor system 8 (e.g., the analyte sensor 10 and the analyte sensor electronics module 12) may be referred to as a "pre-connected" system. The analyte sensor electronics module 12 may wirelessly communicate (e.g., directly or indirectly) with one or more of the display devices 110, 120, 130, and 140. In addition to or in lieu of the display devices 110, 120, 130, and 140, the analyte sensor electronics module 12 may wirelessly communicate (e.g., directly or indirectly) with the partner device 136 and / or the server system 134. Similarly, in some examples, the display devices 110-140 may additionally or alternatively wirelessly communicate (e.g., directly or indirectly) with the partner device 136 and / or the server system 134. The various couplings illustrated in FIG. 1 may be facilitated using a wireless access point 138, as also noted below.

[0076] In certain embodiments, the analyte sensor electronics module 12 includes electronic circuitry associated with measuring and processing the analyte sensor data or information, including predictive algorithms associated with processing and / or calibrating the analyte sensor data / information. The analyte sensor electronics module 12 can be physically / chemically connected to the analyte sensor 10 and can be integral (permanently attached) or removably attached to the analyte sensor 10. The analyte sensor electronics module 12 can also be electrically coupled to the analyte sensor 10 such that the components can be electromechanically coupled to one another. The analyte sensor electronics module 12 can include hardware, firmware, and / or software that enables measurement and / or estimation of the level of an analyte in a host / user via the analyte sensor 10 (e.g., which can / can include a glucose sensor). For example, the analyte sensor electronics module 12 can include a potentiostat, a power supply for powering the analyte sensor 10, other components useful for signal processing and data storage, and a remote measurement module for transmitting data from the sensor electronics module to one or more display devices. The electronics may be fixed, such as to a printed circuit board (PCB) or platform within the analyte sensor system 8, and may take a variety of forms. For example, the electronics may take the form of an integrated circuit (IC), such as an application specific integrated circuit (ASIC), a microcontroller, a processor, and / or a state machine.

[0077] Sensor electronics module 12 may include sensor electronics configured to process sensor information, such as sensor data, and generate transformed sensor data and displayable sensor information. Examples of systems and methods for processing sensor analyte data are described in more detail herein and in U.S. Pat. Nos. 7,310,544 and 6,931,327, and U.S. Patent Publication Nos. 2005 / 0043598, 2007 / 0032706, 2007 / 0016381, 2008 / 0033254, 2005 / 0203360, 2005 / 0154271, 2005 / 0192557, 2006 / 0222566, 2007 / 0203966, and 2007 / 0208245, all of which are incorporated by reference herein in their entireties.

[0078] With further reference to FIG. 1 , display devices 110, 120, 130, and / or 140 may be configured to display (and / or alert) displayable sensor information that may be transmitted by sensor electronics module 12 (e.g., customized data packages transmitted to the display devices based on their respective preferences). Each of display devices 110, 120, 130, or 140 may include a display, such as touchscreen display 112, 122, 132, / or 142 (respectively), to display sensor information and / or analyte data to a user and / or receive input from a user. For example, a graphical user interface (GUI) may be presented to the user for such purposes. In embodiments, the display device may include other types of user interfaces, such as a voice user interface, instead of or in addition to a touchscreen display for communicating sensor information to a user of the display device and / or receiving user input. In embodiments, one, some, or all of the display devices 110, 120, 130, 140 may be configured to display or otherwise convey the sensor information as it is communicated from the sensor electronics module 12 (e.g., in a data package transmitted to the respective display device), without any additional future processing required for calibration and real-time display of the sensor data.

[0079] 1 may include custom display devices, such as analyte display device 110, that are specifically designed to display a particular type of displayable sensor information associated with the analyte data received from sensor electronics module 12 (e.g., in embodiments, numerical values ​​and / or arrows). In an embodiment, one of display devices 110, 120, 130, 140 includes a smartphone, such as mobile phone 120, based on an Android, iOS, or other operating system, configured to display a graphical representation of continuous sensor data (e.g., including current and / or historical data).

[0080] 1 and described above, the system 100 may also include a wireless access point (WAP) 138 that may be used to couple one or more of the analyte sensor system 8, the multiple display devices 110, 120, 130, 140, etc., the server system 134, and the medical device 136 to one another. For example, the WAP 138 may provide WiFi and / or cellular or other wireless connectivity within the system 100. Near field communication (NFC) may also be used between the devices of the system 100 to exchange data and to perform specialized functions, such as waking up or powering up the devices, or causing the devices (e.g., the analyte sensor electronics module 12 and / or the transmitter) to exit a lower power mode or otherwise change state and / or transition to an operational mode. Server system 134 may be used to collect analyte data from analyte sensor system 8 and / or multiple display devices to provide services or feedback including, for example, performing analysis, generating universal or personalized models of glucose levels and profiles, individuals or systems remotely monitoring analyte data, and the like. By way of overview and example, partner device(s) 136 may communicate, typically wirelessly, with analyte sensor system 8, including for authentication of partner device(s) 136 and / or analyte sensor system 8, and for exchange of analyte data, medication data, other data, and / or control signaling, and the like. Partner device 136 may include passive devices in exemplary embodiments of the present disclosure. One example of partner device 136 may be an insulin pump for administering insulin to a user in response to and / or according to the user's analyte levels measured / approximated using analyte sensor system 8. For various reasons, it may be desirable for such an insulin pump to receive and track glucose values ​​transmitted from analyte sensor system 8 (see, for example, FIG. 1 ). One reason for this is to provide the insulin pump with the functionality to interrupt / activate / control insulin administration based on glucose values ​​falling below / above a threshold value.

[0081] Referring now to Figure 2, a system 200 is depicted. System 200 may be used in connection with implementing embodiments of the disclosed systems, methods, apparatus, and / or devices, including, for example, aspects described above in connection with Figure 1. By way of example, various below-described components of Figure 2 may be used to provide wireless communication of analyte (e.g., glucose) data between / among, for example, analyte sensor system 308, display device 310, partner device 315, and / or one or more server systems 334.

[0082] 2, the system 200 may include an analyte sensor system 308, one or more display devices 310, and / or one or more partner devices 315. Additionally, in the illustrated embodiment, the system 200 includes a server system 334, which may include a server 334a coupled to a processor 334c and a storage device 334b. The analyte sensor system 308 may be coupled to the display device 310, the partner device 315, and / or the server system 334 via a communication medium 305. Some details of the processing, collection, exchange of data, and / or performance of actions (e.g., providing medication or related instructions), such as by the analyte sensor system 308, the partner device 315, and / or the display device 310, are provided below.

[0083] The analyte sensor system 308, the display device 310, and / or the partner device 315 may exchange messaging (e.g., control signaling) over the communication medium 305, which may also be used to deliver analyte data to the display device 310, the partner device 315, and / or the server system 334. As alluded to above, the display device 310 may include a variety of electronic computing devices, such as, for example, smartphones, tablets, laptops, wearable devices, etc. The display device 310 may also include the analyte display device 110, which may be customized for display and communication of analyte data and associated notifications, etc. The partner device 315 may include medical devices, such as insulin pumps or pens, connectable devices, such as smart refrigerators or mirrors, key fobs, and other devices.

[0084] In an embodiment, the communication medium 305 may be based on one or more wireless communication protocols, such as, for example, Bluetooth, Bluetooth Low Energy (BLE), ZigBee, WiFi, IEEE 802.11 protocols, infrared (IR), radio frequency (RF), 2G, 3G, 4G, 5G, etc., and / or wired protocols and media. Also, upon review of this disclosure, it will be understood that the communication medium may be implemented as one or more communication links, including separate links between components of the system 200, in some cases, regardless of whether such links are explicitly illustrated in or mentioned in connection with FIG. 2. By way of example, the analyte sensor system 308 may be coupled to the display device 310 via a first link of the communication medium 305 using BLE, while the display device 310 may be coupled to the server system 334 by a second link of the communication medium 305 using a cellular communication protocol (e.g., 4G LTE / 5G, etc.). In an embodiment, the BLE signal may be temporarily attenuated to minimize data interception. For example, attenuation of the BLE signal by hardware or firmware design may be performed temporarily during the brief period of data exchange (e.g., pairing).

[0085] In embodiments, elements of system 200 may be used to perform various processing operations described herein and / or to implement various operations and / or features described herein with respect to one or more of the disclosed systems and / or methods. Upon review of this disclosure, one of ordinary skill in the art will appreciate that system 200 may include single or multiple analyte sensor systems 308, communication medium 305, and / or server system 334.

[0086] As described above, the communication medium 305 may be used to connect or communicatively couple the analyte sensor system 308, the display device 310, the partner device 315, and / or the server system 334 to one another or to a network. The communication medium 305 may be implemented in a variety of forms. For example, the communication medium 305 may include one or more of an Internet connection, such as a local area network (LAN), a person area network (PAN), a wide area network (WAN), an optical fiber network, power line Internet, a hardwired connection (e.g., a bus), DSL, etc., or any other type of network connection or communication coupling. The communication medium 305 may be implemented using any combination of routers, cables, modems, switches, optical fibers, wires, wireless (e.g., microwave / RF, AM, FM links, etc.), etc. Additionally, the communication medium 305 may be implemented using various wireless standards, such as Bluetooth, BLE, Wi-Fi, IEEE 802.11, 3GPP standards (e.g., 2G GSM / GPRS / EDGE, 3G UMTS / CDMA2000, or 4G LTE / LTE-A / LTE-U, 5G, or subsequent generations). Upon reading this disclosure, one of ordinary skill in the art will recognize other ways to implement the communication medium 305 for communication purposes and will also recognize that the communication medium 305 may implement features of the present disclosure using undeveloped communication standards that may be deployed in the future.

[0087] 2, the server 334a may receive, collect, and / or monitor information including analyte data, drug data, and related information from the analyte sensor system 308, the partner device 315, and / or the display device 310, such as input responsive to analyte data or drug data, or input received in connection with an analyte monitoring application executing on the analyte sensor system 308 or the display device 310, or a drug delivery application executing on the display device 310 or the partner device 315. Thus, the server 334a may receive, collect, and / or monitor information from the partner device 315, such as, for example, information regarding the provision of a drug to a user and / or information regarding the operation of one or more partner devices 315. The server 334a may also receive, collect, and / or monitor information regarding a user of the analyte sensor system 308, the display device 310, and / or the partner device 315.

[0088] In an embodiment, the server 334a may be adapted to receive such information via the communication medium 305. This information may be stored in the storage device 334b ​​and processed by the processor 334c. For example, the processor 334c may include an analysis engine capable of performing analysis of the information collected, received, etc. by the server 334a via the communication medium 305. In an embodiment, the server 334a, the storage device 334b, and / or the processor 334c may be implemented as a distributed computing network, such as a Hadoop® network, or as a relational database, etc. Such information may then be processed at the server 334a such that services may be provided to the analyte sensor system 308, the display device 310, the partner device 315, and / or a user(s) thereof. For example, such services may include diabetes management feedback to the user.

[0089] In an embodiment, a database may be implemented on the server system 334 and the communication medium 305 may be used to pair user accounts to one or more analyte sensor systems 308. For example, based on the expected lifespan of an individual component or one or more groups of components of the analyte sensor system 308, or the analyte sensor system 308 as a whole, and / or based on diagnostic feedback received by the analyte sensor system 308, the server system 334 may be able to determine whether a given analyte sensor system 308 or its component or group(s) of components has or has exceeded its useful lifespan. A user may receive an indication, notification, alert, or warning from the server system 334, for example, on the display device 310 and / or via the analyte sensor system 308, that the analyte sensor system 308 or component or group(s) of components has or has exceeded its useful lifespan, or will soon or within a given time. In an embodiment, a user may receive an indication, notification, alert, or warning on the display device 310 from the server system 334 about the expected lifespan of the analyte sensor system 308 or a component or group of components thereof.

[0090] The server 334a may include, for example, an internet server, a router, a desktop or laptop computer, a smartphone, a tablet, a processor, a module, etc., and may be implemented in a variety of forms including, for example, an integrated circuit or collection of integrated circuits, a printed circuit board or collection of printed circuit boards, or a separate housing / package / rack, or any number of thereof. In an embodiment, the server 334a at least partially directs communications that take place over the communication medium 305. Such communications may include delivery of analyte data, drug data, and / or messaging related thereto (e.g., advertisements, authentication, commands, or other messaging). For example, the server 334a may process and exchange messages between and / or among the analyte sensor system 308, the display device 310, and / or the partner device 315 related to frequency bands, timing of transmissions, security / encryption, alarms, alerts, notifications, etc. The server 334a may update information stored in the analyte sensor system 308, the partner device 315, and / or the display device 310, for example, by delivering or updating applications thereto and / or by reconfiguring system parameters or other settings of the analyte sensor system 308, the partner device 315, and / or the display device 310. The server 334a may send and receive information to and from the analyte sensor system 308, the partner device 315, and / or the display device 310 in real-time, periodically, sporadically, or on an event-driven basis. Additionally, the server 334a may implement cloud computing capabilities for the analyte sensor system 308, the partner device 315, and / or the display device 310.

[0091] With the above description of aspects of the disclosed systems and methods for wireless communication of analyte data, examples of certain features of the present disclosure are now provided. Those skilled in the art, upon review of the present disclosure, will understand that these features may be implemented using aspects and / or combinations of aspects of the above exemplary configurations, regardless of whether explicit reference to these features has been made.

[0092] Analyte Data 1, as discussed above, in embodiments, an analyte sensor system 8 is provided for measuring an analyte in a host or user. By way of overview and example, the analyte sensor system 8 may be implemented as an encapsulated microcontroller that performs sensor measurements, generates analyte data (e.g., by calculating values ​​of continuous glucose monitoring data), and engages in wireless communications (e.g., Bluetooth and / or other wireless protocols) to transmit such data to remote devices (e.g., display devices 110, 120, 130, 140, partner device 136, and / or server system 134).

[0093] The analyte sensor system 8 may include an analyte sensor 10 configured to measure a concentration or level of an analyte in a host, and an analyte sensor electronics module 12 that is typically physically connected to the analyte sensor 10 before the analyte sensor 10 is implanted in a user. In an embodiment, the analyte sensor electronics module 12 includes electronics configured to process a data stream associated with an analyte concentration measured by the analyte sensor 10 to generate sensor information including, for example, raw sensor data, transformed sensor data, and / or other sensor data. The analyte sensor electronics module 12 may be further configured to generate sensor information customized for each display device 110, 120, 130, 140, partner device 136, and / or server system 134. The analyte sensor electronics module 12 may be further configured such that different devices may receive different sensor information, and may be further configured to wirelessly transmit the sensor information to such display devices 110, 120, 130, 140, partner device 136, and / or server system 134.

[0094] The term "analyte" as used herein is a broad term and is to be given its ordinary and customary meaning to those skilled in the art (not limited to any special or customized meaning), and further refers to, but is not limited to, a substance or chemical component in a bodily fluid (e.g., blood, interstitial fluid, cerebrospinal fluid, lymphatic fluid, or urine) that may be analyzed. Analytes may include naturally occurring substances, man-made substances, metabolites, and / or reaction products. In some embodiments, the analyte that is subject to measurement by the sensor head, device, and method is glucose. However, acarboxyprothrombin, acylcarnitine, adenine phosphoribosyltransferase, adenosine deaminase, albumin, α-fetoprotein, amino acid profile (arginine (Krebs cycle), histidine / urocanic acid, homocysteine, phenylalanine / tyrosine, tryptophan), andrenostenedione, antipyrine, arabinitol enantiomers, arginase, benzoylecgonine (cocaine), biotinidase, biopterin, c-reactive protein, carnitine, carnosinase, CD4, ceruloplasmin, chenodeoxycholic acid, chloroquine, cholesterol, cholinesterase, conjugated 1-β-hydroxycholic acid, cortisol, creatine kinase, creatine kinase MM isoenzyme, cyclosporin A, d-penicillamine, deoxycholic acid, acetylcholine ... leukotriene, dehydroepiandrosterone sulfate, DNA (acetylation polymorphism, alcohol dehydrogenase, alpha 1-antitrypsin, cystic fibrosis, Duchenne / Becker muscular dystrophy, glucose-6-phosphate dehydrogenase, hemoglobin A, hemoglobin S, hemoglobin C, hemoglobin D, hemoglobin E, hemoglobin F, D Punjab, beta-thalassemia, hepatitis B virus, HCMV, HIV-1, HTLV-1, Leber's hereditary optic neuropathy, MCAD, RNA, PKU, Plasmodium vivax, sex differentiation, 21-deoxycortisol), desbutylhalofantrine, dihydropteridine reductase, diphtheria / tetanus antitoxin, erythrocyte arginase, erythrocyte protoporphyrin, esterase D, fatty acids / acylglycines, free beta-human chorionic gonadotropin, free erythrocyte porphyrin,Free thyroxine (FT4), free tri-iodothyronine (FT3), fumarylacetoacetase, galactose / gal-1-phosphate, galactose-1-phosphate uridyltransferase, gentamicin, glucose-6-phosphate dehydrogenase, glutathione, glutathione peroxidase, glycocholate, glycosylated hemoglobin, halofantrine, hemoglobin variants, hexosaminidase A, human erythrocyte carbonic anhydrase I, 17-α-hydroxyprogesterone, hypoxanthine phosphoribosyltransferase, immunoreactive trypsin, lactate , lead, lipoproteins ((a), B / A-1, β), lysozyme, mefloquine, netilmicin, phenobarbitone, phenytoin, phytanic acid / pristanic acid, progesterone, prolactin, prolidase, purine nucleoside phosphorylase, kinin, inverted tri-iodothyronine (rT3), selenium, serum pancreatic lipase, sisomicin, somatomedin C, specific antibodies (adenovirus, antinuclear antibody, anti-zeta antibody, arbovirus, pseudorabies virus, dengue virus, guinea worm, Echinococcus granulosus, Entamoeba histolytica, enterovirus, Giardia lamblia (giardia duodenalisa, Helicobacter pylori, Hepatitis B virus, Herpes virus, HIV-1, IgE (atopic disease), Influenza virus, Leishmania donovani, Leptospira, Measles / Mumps / Rubella, Mycobacterium leprae, Mycoplasma pneumoniae, Myoglobin, Onchocerca volvulus, Parainfluenza virus, Plasmodium falciparum, Poliovirus, Pseudomonas aeruginosa, Respiratory syncytial virus, Rickettsia (scrub typhus), Schistosoma mansoni, Toxoplasma gondii, Trepenoma pallidium, Trypanosoma cruzi / Langer, Vesicular stomatitis virus virus), Wuchereria bancrofti, Yellow fever virus), Specific antigens (Hepatitis B virus, HIV-1), Succinylacetone, Sulfadoxine, Theophylline, Thyrotropin (TSH), Thyroxine (T4), Thyroxine-binding globulin, Trace elements, Transferrin, UDP-galactose-4-epimerase, Urea, Uroporphyrinogen I synthase, Vitamin A, White blood cells,Other analytes are contemplated, including, but not limited to, zinc protoporphyrin. Salts, sugars, proteins, fats, vitamins, and hormones that occur naturally in blood or interstitial fluids may also constitute analytes in certain embodiments. Analytes, such as metabolites, hormones, antigens, antibodies, and the like, may occur naturally in bodily fluids. Alternatively, analytes, such as contrast agents for diagnostic imaging, radioisotopes, chemical agents, fluorocarbon-based artificial blood, or drugs or pharmaceutical compositions may be introduced into the body, such as insulin, glucagon, ethanol, cannabis (marijuana, tetrahydrocannabinol, hashish), inhalants (nitrous oxide, amyl nitrite, butyl nitrite, chlorohydrocarbons, hydrocarbons), cocaine (crack cocaine), stimulants (amphetamines, methamphetamines, Ritalin, Cylert, Preludin, Didrex, PreState, Voranil, Sandrex, Plegine), depressants (barbiturates, methaqualone, tranquilizers, , e.g., Valium, Librium, Miltown, Serax, Equanil, Tranxene), hallucinogens (phencyclidine, lysergic acid, mescaline, peyote, psilocybin), narcotics (heroin, codeine, morphine, opium, meperidine, Percocet, Percodan, Tussionex, Fentanyl, Darvon, Talwin, Lomotil), designer drugs (fentanyl, meperidine, amphetamine, methamphetamine, and analogs of phencyclidine, e.g., Ecstasy), anabolic steroids, and nicotine. Metabolites of drugs and pharmaceutical compositions are also contemplated as analytes. Analytes such as neurochemicals and other chemicals produced in the body, such as ascorbic acid, uric acid, dopamine, noradrenaline, 3-methoxytyramine (3MT), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5HT), and 5-hydroxyindoleacetic acid (FHIAA), may also be analyzed.

[0095] Pre-Connected Analyte Sensor System As alluded to above with reference to FIG. 1, in embodiments, the analyte sensor 10 comprises a continuous glucose sensor, such as, for example, a subcutaneous, transcutaneous (e.g., transdermal), or intravascular device. In embodiments, such a sensor or device can analyze multiple intermittent blood samples. The analyte sensor 10 can use any method of analyte measurement, including glucose measurement, including, for example, enzymatic, chemical, physical, electrochemical, spectrophotometric, polarimetric, calorimetric, iontophoretic, radiometric, immunochemical, etc.

[0096] In embodiments in which the analyte sensor 10 is a glucose sensor, the analyte sensor 10 may provide a data stream indicative of the glucose concentration in the host using any method, including invasive, minimally invasive, and non-invasive sensing techniques (e.g., fluorescence monitoring), etc. The data stream is typically a raw data signal, which may be converted into a calibrated and / or filtered data stream that can be used to provide a useful glucose value to a user, such as a patient or a caregiver (e.g., a parent, relative, guardian, teacher, doctor, nurse, or any other individual interested in the health of the host).

[0097] The glucose sensor may be any device capable of measuring the concentration of glucose. According to one exemplary embodiment described below, an implantable glucose sensor may be used. However, it should be understood that the devices and methods described herein may be applied to any device capable of detecting the concentration of an analyte, e.g., glucose, and providing an output signal (e.g., as a form of analyte data) representative of the concentration of the analyte, also glucose.

[0098] In an embodiment, the analyte sensor 10 is an implantable glucose sensor as described with reference to U.S. Patent No. 6,001,067 and U.S. Patent Publication No. US2005 / 0027463-A1. In an embodiment, the analyte sensor 10 is a transcutaneous glucose sensor as described with reference to U.S. Patent Publication No. US2006 / 0020187-A1. In an embodiment, the analyte sensor 10 is configured to be implanted in a host vessel or outside the body as described in U.S. Patent Publication No. US2007 / 0027385-A1, co-pending U.S. Patent Publication No. US2008 / 0119703-A1, filed October 4, 2006, U.S. Patent Publication No. US2008 / 0108942-A1, filed March 26, 2007, and U.S. Patent Application No. US2007 / 0197890-A1, filed February 14, 2007. In an embodiment, the continuous glucose sensor includes a transcutaneous sensor, such as described in U.S. Pat. No. 6,565,509 to Say et al. In an embodiment, the sensor 10 is a continuous glucose sensor including a subcutaneous sensor, such as described in U.S. Pat. No. 6,579,690 to Bonnecaze et al., or U.S. Pat. No. 6,484,046 to Say et al. In an embodiment, the continuous glucose sensor includes a refillable subcutaneous sensor, such as described in U.S. Pat. No. 6,512,939 to Colvin et al. The continuous glucose sensor may include an intravascular sensor, such as described in U.S. Pat. No. 6,477,395 to Schulman et al. The continuous glucose sensor may include an intravascular sensor, such as described in U.S. Pat. No. 6,424,847 to Mastrototaro et al.

[0099] Prior to system activation, the analyte sensor electronics module 12 is typically maintained in a lower power mode to conserve or manage battery capacity. The analyte sensor electronics module 12 should generally be reliably activated to begin collecting analyte data in an active power state. For example, it may be preferable not to activate the analyte sensor electronics module 12 until around the time the analyte sensor 10 is implanted into the host. This can help maintain a more accurate sensor calibration, can reduce power consumption, and / or can generally increase analyte measurement accuracy, etc. In some embodiments, activation of the analyte sensor electronics module 12 and / or certain circuitry of the analyte sensor electronics module 12 may occur at least primarily prior to implantation of the analyte sensor 10 (e.g., 5 minutes, 1 minute, 30 seconds, 10 seconds, 1 second, or less than 1 second prior to implantation, etc.). In some embodiments, activation of the analyte sensor electronics module 12 may occur at least primarily or substantially during implantation (e.g., at least partially while the analyte sensor 10 is moving to a deployed position). In some embodiments, operation of the analyte sensor electronics module 12 may occur at least primarily after implantation of the analyte sensor 10 (e.g., less than 1 second, 1 second, 5 seconds, 30 seconds, 1 minute, 3 minutes, 5 minutes, 10 minutes, more than 10 minutes, etc.). In embodiments, the analyte sensor electronics module 12 preferably exits the lower power state at a time around or just before the analyte sensor 10 is implanted. This may allow for a more accurate recording of the time of implantation.

[0100] In a non-preconnected system, the analyte sensor 10 and the analyte sensor electronics module 12 are typically mechanically and electrically connected only after the analyte sensor 10 is implanted in a user. When the analyte sensor electronics module 12 is coupled to an already implanted analyte sensor 10, the electrodes of the analyte sensor electronics module 12 are typically monitored to detect signals related to the analyte. The analyte sensor system 8 can then be actuated in response to the binding and detection of a particular level or characteristic of the analyte in the user. However, in a preconnected analyte sensor system 8, the analyte sensor 10 is electromechanically coupled to the analyte sensor electronics module 12 before the analyte sensor system 8 is delivered to the user, and thus, at the time of sensor implantation, the analyte sensor electronics module 12 is already coupled to the analyte sensor 10. As alluded to above, this pre-binding or pre-connection may lead to false wake-up or actuation from a lower power state due to signals generated by the analyte sensor system 8 prior to sensor implantation (e.g., in situations of high humidity, static electricity, electrical leakage, or noise). Additionally, to improve accuracy in transducing the sensor signal using sensor processing algorithms, it may be preferable that the analyte sensor 10 is not voltage biased by the analyte sensor electronics module 12 prior to implantation.

[0101] Actions that may cause changes in the characteristics of the analyte sensor 10 should generally be minimized prior to implantation. Thus, it may be preferable to avoid or at least reduce the occurrence of voltage bias analyte sensor 10 prior to implantation. By applying a voltage bias to the analyte sensor 10 for a relatively long period of time (e.g., during storage), the service life of the analyte sensor 10 may be shorter than the intended service life following implantation. This may be due, for example, to consumption of reference or enzyme capacity that may be included on the analyte sensor 10. Additionally, analyte processing algorithms that may be used by the analyte sensor system 8 may depend on characterized performance values ​​of the analyte sensor 10. These characterized performance values ​​may include baseline signals, analyte sensitivity, signal drift, lot performance metrics, curve fitting variables, tabulated values, calibration codes, and / or additional factors that may be used as part of the signal processing algorithm in connection with determining the analyte value. Thus, in some cases, particularly for factory calibrated analyte sensors 10, it may be important to make relatively accurate estimates of the performance parameters and / or characteristics of the analyte sensor 10 at the time of implantation into a user to enable accurate generation of analyte values. A significant period of application of a voltage bias across the analyte sensor 10 (e.g., during shelf life) may cause deviations from one or more predetermined performance metrics. This may tend to reduce the accuracy of analyte values ​​determined using sensor processing algorithms to convert one or more measured analyte sensor 10 signals into analyte values ​​after implantation of the analyte sensor 10. Furthermore, deviations from the calibrated state of the analyte sensor 10 during storage may cause the algorithms to report less accurate or inaccurate analyte values.

[0102] Additionally, the amount of power (e.g., mW) used by the circuitry and / or other components (e.g., in the analyte sensor electronics module) that control operation of the analyte sensor system 8 should generally be minimized, reduced, and / or considered in conjunction with making system level performance tradeoffs, where possible. For measurements generated using the analyte sensor 10 or other circuits and components, care should generally be taken to minimize, reduce, and / or control power usage prior to operation of the analyte sensor system 8. The power budget may be limited at least in part by the battery capacity of the analyte sensor system 8. Thus, the analyte sensor system 8 may remain primarily in a lower power or mostly non-operational state prior to operation, and techniques used to control system operation and / or exit a lower power state may consume a small fraction of the available power.

[0103] In embodiments, lower power consumption is achieved, for example, by selecting a reduced or minimum feasible polling or sampling frequency for power usage and detectability of system activation events and / or triggers. In some cases, the sampling or polling frequency used to monitor actuation events / triggers / characteristics may vary based on the type of detection scheme being used (e.g., capacitive measurements versus accelerometer input, as described below). In connection with reducing power consumption, a lower power state machine may be used that performs measurement and logic functions to trigger system wake-up without powering up the main system processor. For example, a lower power state may be effectively maintained by using a reduced and / or variable, adaptable, programmable, and / or configurable polling or sampling frequency. In some cases, this lower power state may be facilitated by the use of a low power state machine. A lower power state that may control / reduce power consumption may be generally maintained in this manner, despite periodic polling / sampling that may be performed in connection with detecting actuation events of the analyte sensor system 8.

[0104] In embodiments, the analyte sensor system 8 is made more robust against false wake-ups, and if a false wake-up is detected, the system may return to a lower power state. For example, if at any time the analyte sensor system 8 detects that the analyte sensor 10 generates a signal that does not meet a threshold or one or more characteristics indicative of a wake-up event, the analyte sensor system 8 may return to or remain in a lower power state. By way of example, in such a lower power state, there may be no data transmission or analyte measurement by the analyte sensor electronics module 12. While in many cases the lower power and active states may be implemented primarily in firmware, some wake-up circuits may have hardware integration to enable a more robust actuation detection mechanism (e.g., discharging a capacitor, as described herein).

[0105] Accordingly, embodiments of the present disclosure involve using a number of techniques and / or mechanisms / components / circuits to detect and confirm that a lower power state of a pre-connected analyte sensor system 8 may change. By way of example, such a change may involve the analyte sensor system 8 being activated, brought out of a lower power state, and / or moved into a more active state. This may occur in response to a condition that indicates that the analyte sensor 10 has been implanted in a user. In one example, the analyte sensor system 8 may detect an analyte using the analyte sensor 10 and a potentiostat or other measurement device that applies a voltage bias to one or more electrodes of the analyte sensor 10 and measures the resulting amount of current that flows. This current and / or associated signal may be referred to herein as a primary signal.

[0106] Additionally, by way of example, there may be a characteristic signal profile that may be measured when the analyte sensor 10 is implanted in the host's tissue. Such a characteristic signal profile may result from changes in the analyte sensor 10 when it is first exposed to a tissue environment, for example, due to membrane hydration and / or resulting changes in analyte and / or ion concentration. Such a characteristic signal profile may be referred to herein as a secondary signal. In embodiments, the secondary signal may include or involve the use of capacitance, impedance, or other electrical measurements of the analyte sensor 10.

[0107] Signal characteristics of a primary signal measured using the analyte sensor 10 (e.g., voltage or current, etc.) along with in vivo and / or factory calibration information of the analyte sensor 10 may be used, for example, by an analyte processing algorithm implemented using the analyte sensor electronics module 12 to convert the primary signal to an analyte concentration level. The signal characteristics of the primary signal may change over time. Examples of signal profiles of analyte values ​​(e.g., which may be measured in mg / dL) or of other measurements made using one or more electrodes of the analyte sensor 10 (e.g., voltage, current, digital "counts," etc.) include the following: signal slope, signal threshold, integral over time, slope, balance, range, or other characteristics that may be used to uniquely identify a signal. Such signal profiles / characteristics may be predefined in the analyte sensor system 8.

[0108] By using a number of the techniques mentioned above and other means such as actuation / state changes in a pre-connected analyte sensor system 8, the implantation of the analyte sensor 10 in the user can be more accurately detected, which in turn has many advantages. For example, accurately detecting or estimating the implantation time of the analyte sensor 10 may better enable a factory calibrated system. As an example, a signal processing algorithm implemented using, for example, the processor 535 of the analyte sensor system 308 (see, for example, FIG. 5) may use one or more techniques in converting the analyte sensor signal to an estimated analyte value. During various periods of the life cycle of the analyte sensor 10 (e.g., less than 1 hour after implantation, less than 4 hours after implantation, more than 4 hours after implantation, etc.), these conversion techniques may provide different levels of accuracy in terms of the precision of the conversion. In embodiments, some of these techniques may rely on a predetermined signal profile that is time-dependent. Thus, recording and / or estimating a more accurate implantation time of the analyte sensor 10 may be beneficial in selecting a signal processing algorithm and in addressing variations in the processing techniques that may occur as a function of time. Thus, an analyte sensor system 8 employing such techniques / means may have improved overall accuracy, as well as improved performance upon implantation of the analyte sensor 10 (as performance upon implantation may be affected, including, for example, due to errors that may be induced by not accurately assessing / detecting the time at which the analyte sensor 10 is implanted). For example, inaccuracies may be introduced due to a slope in the sensitivity of the analyte sensor 10 following implantation, or due to background signal changes that may occur following implantation of the analyte sensor 10.

[0109] Accurate detection of the implantation time may also allow for faster start-up of the analyte sensor system 8 in terms of providing analyte information to a user. For example, a more accurate implantation time may be useful for determining the appropriate point (e.g., the confidence between the signal and the analyte conversion) for an analyte calculation algorithm implemented in the analyte sensor system 8 to begin displaying analyte information to a user. Due to the slope of the analyte-related signal change within a first period (such as, for example, 2 hours) after implantation of the analyte sensor 10, implantation timing errors may result in inappropriate predictions for the signal response and analyte signal. By recognizing the time point of the characteristic signal decay curve, the analyte sensor system 8 and / or devices operating in conjunction with the analyte sensor system 8 may display or provide analyte information (e.g., on display devices 110, 120, 130, 140, to server system 134, and / or to partner device(s) 136, see for example FIG. 1 ) relatively sooner (e.g., within 2 hours, 1 hour, 30 minutes, 15 minutes, or less) than if the implantation time of the analyte sensor 10 was not precisely determined.

[0110] Additionally, accurate detection of the implantation time of the analyte sensor 10 can assist in preventing reuse of the analyte sensor 10. Detection of the sensor implantation time by the electronics module 12 can allow for a higher reliability metric relative to relying on the user to provide notification of the insertion / implantation time. For example, the disconnection and / or implantation characteristics can distinguish a newly inserted analyte sensor 10 from an attempt by a user to restart an expired analyte sensor 10.

[0111] As an additional example, accurate detection / estimation of the implantation time of the analyte sensor 10 may enable faster connection establishment between the analyte sensor electronics module 12 and devices connectable to the analyte sensor electronics module 12 (see, e.g., FIG. 1). With more accurate detection and / or estimation of the implantation time of the analyte sensor 10, the analyte sensor system 8 may be placed in a state to establish and communicate with multiple devices based on being at or near the time of implantation. For example, the analyte sensor system 8 may be capable of transitioning to a pairing state within a relatively short period of implantation (e.g., less than 10-15 minutes) such that a display device (e.g., with reference to, e.g., FIG. 1, display devices 110, 120, 130, 140, partner device(s) 136, etc.) may be capable of wirelessly connecting to the analyte sensor system 8. Also, more accurate detection of the implantation time of the analyte sensor 10 may be used to trigger alternate connection profiles to facilitate faster connections, such as pairing, encryption, advertisement characteristics, etc. That is, for example, a more deterministic wake-up event may be used to facilitate a more aggressive connection model, such as between the analyte sensor system 8 and devices connectable to the analyte sensor system 8 (e.g., sending advertisement packets at a faster rate, etc.). This may allow for faster connection establishment and may provide near real-time feedback to the user that the analyte sensor system 8 is receiving a signal and is connected to a display device.

[0112] An additional example of an advantage associated with accurate estimation of the implantation time of the analyte sensor 10 that may be enabled by a more robust wake-up technique for the analyte sensor 8 is improved error detection. By knowing the predicted profile and monitoring the signal measured using the analyte sensor 10 from the time of implantation, deviations in the signal profile from the expected characteristics of implantation can be recognized. This may be enabled by knowledge of the implantation time of the analyte sensor 10 as well as the ability to analyze the analyte signal at the time of implantation (e.g., a signal associated with implantation is less likely to be missed because the analyte sensor system 8 is in a lower power state). The ability to recognize such deviations may trigger errors in the safety or accuracy of the system that may be dangerous to a user of the analyte sensor system 8. For example, an analyte sensor 10 that is physically damaged (e.g., membrane breaks, tears, manufacturing errors, etc.) may have a different characteristic signal after implantation.

[0113] Yet another example of an advantage associated with accurate estimation of the implantation time of the analyte sensor 10 is a faster wake-up time of the analyte sensor system 8, which may also allow for improved error detection capabilities. The risk of user variability in the implantation time of the analyte sensor 10 may be reduced by using a pre-connected analyte sensor system 8 and by automatically or semi-automatically detecting the implantation time of the analyte sensor 10. An analyte sensor 10 inserted in an incorrect tissue location (e.g., not subcutaneously or into a muscle / fascia other than the desired tissue layer) may have a different characteristic signal than expected following insertion. A faster wake-up time may allow such issues to be detected more quickly following implantation, improving the overall error detection performance associated with the analyte sensor system 8.

[0114] FIG. 3A shows a perspective view of an on-skin sensor assembly 360 that may be used in conjunction with a pre-connected analyte sensor system 8, according to some embodiments. For example, the on-skin analyte sensor assembly 360 may include the analyte sensor system 8, with reference to FIG. 1 as an example. The on-skin sensor assembly 360 may include an outer housing including a first upper portion 392 and a second lower portion 394. In an embodiment, the outer housing may include a clamshell design. The on-skin sensor assembly 360 may include components similar to the analyte sensor electronics module 140 described above in connection with FIG. 1, such as a potentiostat, a power supply for powering the analyte sensor 10, signal processing components, data storage components, and a communication module (e.g., a telemetry module) for one-way or two-way data communication, a printed circuit board (PCB), an integrated circuit (IC), an application specific integrated circuit (ASIC), a microcontroller, and / or a processor.

[0115] As illustrated in FIG. 3A, the outer housing may be characterized by a generally oval shape. The outer housing may further include an opening 396 disposed substantially through a central portion of the outer housing and adapted for insertion of the sensor 338 through the bottom of the on-skin sensor assembly 360 and a needle. In an embodiment, the opening 396 may be a channel or an elongated slot. The on-skin sensor assembly 360 may further include an adhesive patch 326 configured to secure the on-skin sensor assembly 360 to the skin of a host. In an embodiment, the adhesive patch 326 may include an adhesive suitable for skin adhesion, such as a pressure sensitive adhesive (e.g., acrylic, rubber, or other suitable type) bonded to a carrier substrate (e.g., spunlace polyester, polyurethane film, or other suitable type) for attachment to the skin, although any suitable type of adhesive is also contemplated. As shown, the adhesive patch 396 may feature an opening 398 aligned with the opening 396 such that the sensor 338 may pass through the bottom of the on-skin sensor assembly 360 and the adhesive patch 396 .

[0116] Figure 3B shows a bottom perspective view of the on-skin sensor assembly 360 of Figure 3A. Figure 3B further shows an opening 396 disposed substantially in a central portion of the bottom of the on-skin sensor assembly 360, and an opening 398, both adapted for sensor 338 and needle insertion.

[0117] Figure 4 shows a cross-sectional view of the on-skin sensor assembly 360 of Figures 3A and 3B. Figure 4 shows a first upper portion 392 and a second lower portion 394 of the outer housing, an adhesive patch 326, an opening 396 in a central portion of the on-skin sensor assembly 360, an opening 398 in the central portion of the adhesive patch 326, and a sensor 338 passing through the opening 396. The electronics unit described above in connection with Figure 3A may further include a circuit board 404 and a battery 402 configured to provide power to at least the circuit board 404.

[0118] 5, a more detailed functional block diagram of the analyte sensor system 308 (e.g., discussed above in connection with FIGS. 1 and 2) is provided. As illustrated in FIG. 5, the analyte sensor system 308 may include an analyte sensor 530 (which may also be designated, e.g., as 10 in FIG. 1) coupled to an analyte sensor measurement circuit 525 for processing and managing sensor data. The sensor measurement circuit 525 may be coupled to a processor / microprocessor 535 (which may be part of item 12 in FIG. 1, for example). In some embodiments, the processor 535 may perform some or all of the functions of the sensor measurement circuit 525 to obtain and process sensor measurements from the sensor 530.

[0119] The processor 535 may further be coupled to a wireless unit or transceiver 510 (which may be part of item 12 of FIG. 1, for example) for transmitting sensor and other data and receiving requests and commands and other signals from an external device such as a display device 310 (see, for example, FIG. 2). The display device 310 may be used to display or otherwise provide the sensor data (or analyte data) or data derived therefrom to a user, a server system 334, and / or a partner device 315. The partner device 315 may utilize the sensor data or derived data derived therefrom in administering medications (e.g., insulin) and / or in diabetes management guidance to the user. As used herein, the terms "wireless unit" and "transceiver" may be used interchangeably and generally refer to devices that can transmit and receive data wirelessly. The analyte sensor system 308 may further include a memory device 515 (which may be part of, for example, item 12 in FIG. 1 ) and a real-time clock (RTC) 540 (which may be part of, for example, item 12 in FIG. 1 ) for storing and tracking sensor data and other data.

[0120] The analyte sensor system 308 may also include an actuation detection circuit 520. The actuation detection circuit 520 may optionally operate in conjunction with an actuation detection component 545. The actuation detection component 545 may be integrated into the analyte sensor system 308, may be a component attachable to the analyte sensor system 308, and / or may be external to the analyte sensor system 308. Examples of the actuation detection circuit 520 may include one or more of: (1) a measurement circuit that measures an electrical characteristic associated with the analyte sensor 10, such as capacitance or impedance; (2) a proximity detection circuit that may use, for example, capacitive sensing, inductive sensing, magnetic sensing, sonic detection, etc.; (3) a temperature measurement circuit; (4) an accelerometer circuit; (5) an NFC / RFID radio and / or antenna circuit; (6) an air pressure detection circuit; (7) an audio circuit; (8) an optical detection circuit; (9) a conductivity measurement circuit; (10) a switch detection circuit; (11) a strain detection circuit; and the like. The actuation detection circuit 520 and / or actuation detection component 545 may also use or include logic circuitry adapted to execute stored instructions or computer code to perform functions as described herein with respect to detecting actuation events / triggers based on triggering events / conditions and / or measurements of analytes / characteristics / profiles and otherwise enabling operation of the analyte sensor system 8. Additional details regarding the actuation detection circuit 520 and actuation detection component 545 are further discussed elsewhere herein.

[0121] The analyte sensor system 308 of the example implementation collects analyte data using a sensor 530 and transmits the analyte data or a derivative of the analyte data to the display device 310, the partner device 315, and / or the server system 334. Data points regarding the analyte value may be collected and transmitted over the life of the sensor 530. New measurements and / or related information may be transmitted frequently enough for a remote device / individual to adequately monitor the analyte (e.g., glucose) level.

[0122] It should be understood that many details of processing, collecting, and exchanging data by the analyte sensor system 308, partner device 315, and / or display device 310, etc., are provided elsewhere herein. Upon review of this disclosure, it will be understood that the analyte sensor system 308 may, for at least some embodiments herein, include some similar components as described with respect to FIG. 1 or FIG. 2. Thus, details and use of such similar components may be understood for the analyte sensor system 308 even if not explicitly described herein with reference to FIG. 5.

[0123] Exiting a low power state As discussed above, embodiments of the present disclosure relate to the timing for actuating the analyte sensor system 308 or causing it to exit a lower power mode, particularly if the analyte sensor system 308 is a pre-connected system. For example, in such a pre-connected system, the analyte sensor 10 may be mechanically and electrically coupled to the analyte sensor electronics module 12 before the analyte sensor 10 is implanted in a host. There are several different time periods during which the analyte sensor system 308 may exit a lower power mode, each time period typically having an associated trade-off.

[0124] One time period during which the analyte sensor system 308 may exit a lower power state is when a user opens a package containing the analyte sensor system 308 or when the user removes the analyte sensor system 308 from such package. For example, a switch, magnet, or other means as described herein may be used to cause the analyte sensor system 308 to exit a lower power state in response to opening a shipping box or sterilization pack for the analyte sensor system 308, in response to removal of a cap / lid on the system, and / or in response to peeling of the foil / Tyvek packaging of the system. However, exiting a lower power state during this time period may likely not be immediately prior to insertion of the analyte sensor 10 into the user, thus potentially increasing the power usage requirements of the analyte sensor system 308. For example, if multiple analyte sensor systems 308 are typically delivered to a user in a single package (e.g., a four-pack), all of the delivered analyte sensor systems 308 may be activated in this scenario, even though only one of the analyte sensor systems 308 may likely be used in the near future. In another example, after a user removes the packaging lid of the analyte sensor system 308, thus triggering the analyte sensor 10 to be biased, it is possible to delay implantation of the analyte sensor 10 until the analyte sensor 10 is biased or other secondary verification means are used, thus wasting power used to use such secondary verification means (e.g., NFC, accelerometer, impedance measurement, etc., as described in detail herein) and potentially reducing the accuracy of the analyte sensor 10 due to calibration drift that may result from applying a bias.

[0125] Another exemplary time period during which the analyte sensor system 308 may exit a lower power state is when the analyte sensor system 308 is in the applicator but not yet deployed. Exemplary techniques that may be used to exit a lower power state during this time period include mechanical means (e.g., a bridge, etc.) and electrical or other non-mechanical means (e.g., NFC, magnetic, sonic detection, etc.), as discussed in more detail below. In certain circumstances, this time period may be preferred because it may be easier to detect actuation events, for example because typically detectable events that may occur during this time period (e.g., the analyte sensor system 308 changing position relative to the applicator) may occur for a longer period of time compared to detectable events that may be associated with, for example, the deployment of the analyte sensor system 308. This time period may be preferred for detecting indicators related to actuation, as it is typically closer in time to the implantation of the analyte sensor 10, thus helping to reduce false wake-ups created by the user, such as may occur when the user unpacks the analyte sensor system 308 but subsequently chooses not to implant the analyte sensor 10. Thus, events that may occur at the applicator of the analyte sensor system 308 may act as more effective markers for estimating implantation time and / or for activating the analyte sensor system 308 or causing it to exit a lower power state.

[0126] Yet another period during which the analyte sensor system 308 may be caused to exit a lower power state is during deployment of the analyte sensor system 308 (e.g., movement of the analyte sensor 10 from a proximal to a distal position into the host's tissue). Again, either electrical or electromechanical means, or both, may be used to trigger activation of the analyte sensor system 308. However, one potential problem with using a deployment-related event for actuation purposes is that because deployment typically occurs over a shorter period of time than an actuation-related indicator, such as that occurring in association with an applicator (as discussed above), the signal or event may be easily overlooked or difficult to detect for an applicator-related event.

[0127] Another time period that may be used to cause the analyte sensor system 308 to exit the lower power state may be after implantation of the analyte sensor 10. Mechanical, electrical, and / or electromechanical (or other non-mechanical) means may be used to trigger operation of the analyte sensor system 308. Additionally or alternatively, the analyte sensor 10 itself may be used to trigger the analyte sensor system 308 to wake up or exit the lower power state. As an example, the measured capacitance of the analyte sensor 10, and / or the measured value of the sensor's membrane impedance, and / or the measured value of the user's skin impedance may be compared to a known condition (e.g., a threshold value) and the comparison may be used to indicate implantation of the analyte sensor 10. However, any delay in detecting the insertion of the analyte sensor 10 after insertion of the analyte sensor 10 may affect the accuracy of the analyte processing algorithms used to calculate the analyte value. Furthermore, such delays may affect the ability of the analyte sensor system 308 to perform other operations that it may perform, such as pairing with a display device 310, a partner device 315, etc., communicating analyte values ​​to the display device 310, the partner device 315, etc.

[0128] USING A SIGNAL FROM AN ANALYTE SENSOR TO EXIT A LOWER POWER STATE - Patent application As mentioned above, embodiments of the present disclosure involve detecting implantation of the analyte sensor 10 in a user, including, for example, when implantation is detected using the analyte sensor 10, and having the analyte sensor system 308 activate and / or exit a lower power state in an accurate and power efficient manner. In an exemplary embodiment, an analyte signal from the analyte sensor 10 is used for actuation purposes. For example, the actuation detection circuit 520 may use one or more signals from a potentiostat to generate an analyte signal and / or detect / measure, for example, current flow through the analyte sensor 10 (or analyte sensor 530 with reference to FIG. 5, although these components may be referred to interchangeably in some cases) over time. Such signals may be quantified in units such as pA (current flow), pW (power), or counts (digital values ​​converted from analog values ​​such as voltage, current, power, and / or time), and these values ​​may be used for purposes of triggering the analyte sensor system 308 to exit a lower power state. For example, a benchmark threshold in units of current may be used to trigger wake-up or operation of the analyte sensor system 308. However, basing such triggering on a predetermined threshold in units of current (e.g., counts) may result in false wake-ups or missed wake-ups. For example, if the analyte sensor 10 is not properly embedded in the host (e.g., due to electrostatic discharge that may occur while the analyte sensor 10 is packaged and prior to deployment), the predetermined threshold may be met, causing the analyte sensor system 308 to wake up or transition to an operational mode in a situation where it should remain in a lower power state or storage mode.

[0129] Thus, embodiments of the analyte sensor system 308 generally use a benchmark threshold (e.g., approximately X counts, where X may be, for example, 9000 counts) for measurements of the analyte sensor 10 current, which may be measured over a particular time period in seconds or minutes (e.g., 300 seconds or 5 minutes). In certain embodiments, the benchmarked threshold may be monitored against a sustained condition, where the benchmarked threshold is configured to be reached or exceeded for a predetermined time period before actuation is triggered, and thus may help ensure that the analyte sensor system 308 should wake up reliably. For example, the sustained condition may include a consistent frequency of current measurements (e.g., including digital counts in some cases) over a subset of the duration used to measure the current for actuation purposes. For example, this may ensure that the benchmark threshold is not reached based on undesired anomalies, such as short-term spikes in current (or, for example, digital counts) within a period for monitoring the current through the analyte sensor 10 for actuation purposes of the analyte sensor system 308.

[0130] The measured current (e.g., number of counts received) of the analyte sensor 10 may be compared to a benchmark threshold (e.g., X counts, which may be approximately 9000 counts). Upon determining that the measured current (e.g., number of counts received) reaches or exceeds the benchmark threshold (e.g., X counts), the processor 535, which may be part of or operate in conjunction with the operation detection circuit 520, may initiate an operation mode of the analyte sensor system 308. For example, the analyte sensor system 308 may begin receiving / acquiring sensor information from the analyte sensor 530. In some embodiments, for example, the estimated analyte value data is then transmitted to one or more display devices 110, or the like. That is, the processor 535 may remain active and transfer / communicate and / or process the sensor information (e.g., current, digital counts, etc.) to the transceiver 510 for communication with one or more display devices 110, partner device 136, or the like. However, if it is determined that the measured current (e.g., the number of digital counts received, etc.) has not reached or exceeded the benchmark threshold (e.g., X counts), the analyte sensor system 308 may remain in the lower power state and / or storage mode. Optionally, in some cases, following a determination that the measured current (e.g., the number of counts received, etc.) has reached or exceeded the benchmark threshold (e.g., a threshold associated with the counts), another determination may be made to determine whether the measured value (e.g., the number of counts received, etc.) has reached or exceeded a second benchmark (e.g., a count threshold (U)) for a second period of time (V). This may result in a system that is more robust against false wake-ups that may result from anomalies associated with the analyte sensor signal.

[0131] 7A is a schematic diagram of an equivalent circuit model 700 of an analyte sensor 10 according to an embodiment of the present disclosure. The sensor circuit model 700 can represent electrical characteristics of an analyte sensor 10, such as an embodiment of a continuous glucose sensor. The circuit 700 includes a first terminal 704 (which can be, for example, a working electrode) and a second terminal 702 (which can be, for example, a reference electrode). Operatively connected in series to the second terminal 702 is an Rsolution 712 that represents a resistance of a bulk 706 between the first terminal 704 and the second terminal 702. The bulk 706 can be a liquid (e.g., interstitial fluid) or other medium in which the analyte sensor 10 is disposed, such as a buffer solution in an example of a bench laboratory study or in an example of use as a subcutaneously disposed analyte sensor 10, and the bulk 706 can represent the subcutaneous tissue environment between the first terminal 704 and the second terminal 702.

[0132] Operatively connected to Rsolution 712 are Cmembrane 716, which represents the capacitance of the membrane 708 of the analyte sensor 10, and Rmembrane 714, which represents the resistance of the membrane 708 of the analyte sensor 10. Operatively connected to Rmembrane 714 is a parallel network of Cdouble layer 718 and Rpolarization 720. The parallel network of Cdouble layer 718 and Rpolarization 720 represents the reaction occurring at the surface of the platinum interface of the first terminal 704. In particular, Cdouble layer 718 represents the charge accumulated when the working electrode (e.g., platinum) is in the bulk 706, and Rpolarization 720 is the polarization resistance of the electrochemical reaction that may occur at the working electrode interface 710.

[0133] In an exemplary embodiment, a non-analyte signal is generated using the analyte sensor 10 and used to activate the analyte sensor system 308 and / or cause the analyte sensor system 308 to exit a lower power mode. One such non-analyte signal includes a signal that may represent a particular electrical, physical, or other characteristic of the analyte sensor 10. For example, the stimulus signal may be used to determine a particular characteristic of the analyte sensor 10.

[0134] According to an embodiment, the capacitance of the analyte sensor 10 may be detected and used to trigger the analyte sensor system 308 to activate and / or exit a lower power state. For example, the capacitance of the analyte sensor 10 may change when the membrane of the analyte sensor 10 is hydrated or placed in an environment having a higher or lower humidity. The actuation detection circuit 520 may include circuitry that responds to the capacitance of the analyte sensor 10 and drives a time-varying signal (e.g., a square wave, a voltage step, an AC signal, etc.) through the analyte sensor 10 and detects how the signal is affected by the capacitance of the analyte sensor 10. How the analyte sensor 10 responds to the drive signal may be indicative of the capacitance associated with the analyte sensor 10. For example, a minimum level of capacitance of the analyte sensor 10 may be required to detect a threshold response to the drive signal. Thus, the analyte sensor system 308 can use the actuation detection circuit 520 to measure a metric indicative of the capacitance of the analyte sensor 10 and can make a determination as to whether the analyte sensor 10 is embedded in the host based on the capacitance metric. It should be understood that the measured capacitance can include one or more of the Cmembrane 716, the Cdouble layer 718, and other capacitances associated with the analyte sensor 10 (see FIG. 7A for an example). For example, a drive signal can be passed through the analyte sensor 10 between the first terminal 702 and the second terminal 704, where the drive signal is affected by the Cmembrane 716, the Cdouble layer 718, and other capacitances that may be associated with the analyte sensor 10 and can be used to estimate the total amount of capacitance that may load the analyte sensor 10 and / or the capacitances.

[0135] Impedance is another characteristic of the analyte sensor 10 that may be detected and used to trigger the analyte sensor system 308 to activate and / or exit a lower power state. FIG. 7B illustrates an example plot 726 of impedance value (e.g., in ohms) 722 of the analyte sensor 10 versus time (e.g., in seconds) since implantation 724. As illustrated, the impedance value 722 of the analyte sensor 10 may begin to decrease after a period of time (e.g., 30 seconds) following implantation. As further illustrated, after an initial decay in the impedance value 722, the impedance value 722 generally stabilizes following a period of time following implantation of the analyte sensor 10. Changes that may result from implantation of the analyte sensor 10 (e.g., a decrease in the impedance value 722, or a rate of change in the impedance value, etc.) may be used to detect / trigger actuation.

[0136] 7C illustrates another example plot 734 of impedance values ​​730 (e.g., in units of ohms). FIG. 7C provides a plot of impedance values ​​730 versus hydration 732 (e.g., in units of %), where hydration 732 may be hydration associated with the membrane of the analyte sensor 10. In general, humidity outside the human body may cause a membrane hydration level that may be lower than the hydration level that may normally be associated with the membrane when the analyte sensor 10 is inside the human body. Thus, moisture in the environment and the resulting hydration level (e.g., of the membrane of the analyte sensor 10) may be used to indicate whether the analyte sensor 10 is or is not implanted within the host's body. Additionally, in some cases, certain environmental conditions (e.g., humidity) may cause the analyte sensor system 308 to operate even when the analyte sensor 10 is not inserted into the host's body.

[0137] Additionally, measurable electrical properties associated with the analyte sensor 10 may vary as a function of environmental humidity, moisture, and / or membrane hydration. Variations in such measurable electrical properties (e.g., impedance, capacitance, etc.) as a function of humidity, moisture, and / or hydration may, in some cases, result in the measurable electrical properties serving as a more reliable indicator to activate the analyte sensor system 308 or, for example, cause the analyte sensor system 308 to exit a lower power state rather than using the humidity, hydration, and / or moisture levels directly. For example, in some cases, humidity, moisture, and / or membrane hydration may increase for reasons other than the analyte sensor 10 being inserted into a host (e.g., high moisture levels in the packaging of the analyte sensor system 308) and thus trigger a false wake-up of the analyte sensor system 308. Thus, the relationship between humidity / moisture and certain measurable electrical properties of the analyte sensor 10 (e.g., impedance, capacitance, etc.) may be utilized to more accurately detect an insertion event of the analyte sensor 10 and activate the analyte sensor system 308 in response thereto.

[0138] For example, under lower humidity conditions (e.g., 90% RH), the impedance may be relatively high (e.g., 10 MΩ). However, once the analyte sensor 10 is implanted, the impedance may decrease relatively quickly (e.g., to hundreds of kΩ) in some cases. Thus, in embodiments, the change, rate of change, and / or threshold impedance value (e.g., approximately 300-500 kΩ as a specific but non-limiting example) may be used to distinguish between high humidity conditions that may occur in a non-inserted environment outside the host's body, on the one hand, and moisture conditions that may occur in association with the analyte sensor 10 being implanted within the host's body, on the other hand. This may help to prevent (or resist) environmental conditions from triggering the analyte sensor system 308 to activate or exit a lower power state when it is undesirable to do so. The desired level of the impedance threshold can be based on the time that can be allocated to a wake-up trigger time window of the analyte sensor system 308 after insertion of the analyte sensor 10, and can be a trade-off between the robustness of the state against false wake-ups based on, for example, noise, signal magnitude, measurement inaccuracies of the circuitry, etc. Examples of feasible wake-up trigger times include, but are not limited to, approximately 30 seconds or less to approximately 60 seconds or more.

[0139] 7C, at hydration 736 (e.g., in %) prior to implantation of the analyte sensor system 10, point 740 on plot 734 corresponds to impedance value 738 (e.g., in Ω). Additionally, at subsequent hydration 756 after implantation of the analyte sensor 10, point 760 corresponds to impedance value 758. In an embodiment, impedance value 758 may be appreciably lower than impedance value 738, such that a range of impedance values ​​between impedance value 744 and impedance value 750, corresponding to points 746 and 752, respectively, on plot 734, may be used as a threshold for detecting implantation of the analyte sensor 10, and thus may be used to trigger the analyte sensor system 308 to activate and / or exit a lower power state. In additional or other examples, the slope or derivative of the impedance value as a function of hydration may be monitored to detect implantation of the analyte sensor 10. Thus, for example, the impedance of the analyte sensor 10 may be monitored, and an actuation or change in state of the analyte sensor system 308 may be triggered when the impedance crosses an impedance threshold (e.g., or achieves a threshold differential, slope, or other condition). In a particular example, the analyte sensor 10 may have an impedance associated with it of approximately 10 MΩ at a relatively lower hydration value (e.g., within a range of values ​​typical for environmental humidity outside the host's body or within a particular environment) prior to insertion of the analyte sensor 10. Then, after the analyte sensor 10 is inserted into the user's body, as hydration increases, the impedance value of the analyte sensor 10 may decrease to approximately 100 kΩ.

[0140] The impedance associated with the analyte sensor 10 may be measured using a variety of techniques, including, for example, using a voltage or current step or other function, using electrochemical impedance spectroscopy (e.g., as described in U.S. Pat. No. 9,801,575, which is incorporated herein by reference in its entirety), or using any other known method. By way of example, the actuation detection circuit 520 may include a driver circuit (e.g., a function generator, oscillator, etc.) operating to generate a step function or other function or signal that may be used to measure the impedance of the analyte sensor 10. For example, a voltage associated with the step function or other signal may be applied to the analyte sensor 10, such that a resulting current between terminals of the analyte sensor 10 may be detected using the actuation detection circuit 520. In an exemplary implementation, the relationship between the applied voltage and the resulting current may then be used to calculate the impedance of the analyte sensor 10.

[0141] In general, to reduce / minimize battery power usage and avoid sending more current to the analyte sensor 10 than is necessary or appropriate, any impedance measurements taken for actuation purposes should use a relatively low amplitude waveform (e.g., less than approximately 50 mV), preferably zero net current (e.g., centered around an electrode voltage bias of 0 V). In an embodiment, as discussed above, a measurement indicative of impedance may be characterized using actuation detection circuit 520 by applying a voltage (e.g., a step function) to the analyte sensor 10. The magnitude of the resulting current flow (which may include, e.g., a current spike) may be inversely proportional to the impedance of the membrane of the analyte sensor 10. Thus, using Ohm's law, for example, but not limited to, impedance may be determined by monitoring the voltage, current, and / or digital counts of one or both.

[0142] The actuation detection circuit 520 may include circuitry that detects whether the impedance is above or below a set level. Such circuitry is discussed in more detail below in connection with at least FIG. 8A and FIGS. 12-14. With reference to FIG. 8A, at a high level, the circuitry may capture a positive current spike using, for example, a switch that may be driven using a voltage source that may apply a square wave or other waveform to the analyte sensor 10. The positive current may then be used to charge a capacitor. The voltage that may develop across the capacitor may represent a measurement of the impedance of the analyte sensor 10 (e.g., as measured based on a voltage divider that may be placed between the impedance of the analyte sensor 10 and a known impedance). By using a voltage comparator circuit set to a desired level, the insertion of the analyte sensor 10 may be determined and the insertion of the analyte sensor 10 may be used to trigger the analyte sensor system 308 to exit a lower power state. Such circuitry may be designed and integrated into a chip that can operate at very low power (e.g., less than 1 uA during the lower power state). Upon detecting implantation of the analyte sensor 10, the chip and / or circuitry can send a control signal to the processor 535 causing the analyte sensor system 308 to exit the lower power state.

[0143] In an embodiment, a voltage-to-current amplifier and additional switches may be used to disconnect the analyte sensor 10 from the detection circuitry after the analyte sensor system 308 exits a lower power state. It should also be noted that under high humidity conditions (e.g., as may occur during storage), the net current through the analyte sensor 10 may be limited. This may provide an advantage over approaches for operation of the analyte sensor system 308 that apply a fixed bias (e.g., a voltage such as 0.6 V) to the analyte sensor 10. If such an approach is used, under high humidity conditions, the current flowing through the analyte sensor 10 as a result of the application of the fixed bias may consume an undesirable amount of power and / or may affect the performance of the analyte sensor 10.

[0144] Turning now to FIG. 8A, an exemplary actuation detection circuit 800 is illustrated in accordance with an embodiment of the present disclosure. The circuit 800 may be used, for example, to detect current in a lower power wake-up circuit that may be used to actuate the analyte sensor system 308. At a high level, and referring to FIG. 5 as an example and context of a particular embodiment, the circuit 800 may use an inrush (e.g., charging) current through the capacitance of the analyte sensor 530 to generate a voltage pulse. The voltage pulse may be monitored by the detection circuit and may trigger the analyte sensor system 308 to exit a lower power state if the pulse meets one or more conditions. As an example, in a particular embodiment, a predetermined number of pulses exceeding a voltage threshold may trigger actuation of the analyte sensor system 308. Additional examples are described below.

[0145] Components such as one or more switches and one or more current limiting resistors may be used in the circuit 800 to provide a more accurately detectable implantation event of the analyte sensor 530 and therefore a more robust control for causing the analyte sensor system 308 to activate or exit a lower power mode. For example, at a first time, a switch may be used to couple a first terminal of the analyte sensor 530 to a potentiostat or other measurement device or circuit. The detection circuit may include an amplifying element (e.g., a comparator, a low noise amplifier, other amplifiers, etc.) and / or other circuitry in certain examples. The detection circuit may be used to detect whether a voltage generated using the circuit 800 exceeds a threshold or otherwise achieves one or more conditions, for example, based on a current that may flow (e.g., charging) through a capacitance of the analyte sensor 530. If the voltage exceeds a condition(s) or otherwise achieves a condition(s), activation of the analyte sensor system 308 may be triggered. For example, such a voltage may be generated using the current-voltage conversion action of components that may be included in or used by circuit 800 , such as capacitor 834 , switch element 818 , and / or driver circuit 806 .

[0146] Then, for example, at a second time, a switch that may be used to couple the first terminal of the analyte sensor 530 to a measurement device (e.g., a potentiostat) may be opened or placed in a high impedance state to isolate the first terminal of the analyte sensor 530 from the measurement device / potentiostat, while a second switch may couple the first and second terminals of the analyte sensor 530 together, for example, via a current limiting resistor, to at least substantially discharge the capacitance of the analyte sensor 530. In this manner, a potential that may exist across the analyte sensor 530 may be set, reset, and / or zeroed. This may effectively reset the circuit such that the inrush event of charging current through the capacitance of the analyte sensor 530 may be repeated, thus allowing another detectable event and providing a more robust actuation detection mechanism for the analyte sensor system 308. In some cases, this actuation detection mechanism may more reliably distinguish between multiple electrical characteristics that may be measured for the analyte sensor 530, where some such electrical characteristics may indicate a hydration state of the analyte sensor 530 and other such characteristics may simply indicate a high humidity environment and allow the analyte sensor system 308 to operate more properly, reliably, or accurately.

[0147] More specifically, FIG. 8A illustrates that circuit 800 may include an analyte sensor 808 and a measuring device 810 (e.g., a potentiostat). It will be understood by those of skill in the art upon studying this disclosure that in certain embodiments, analyte sensor 808 may be similar, substantially similar, or the same as analyte sensor 530 referenced in connection with FIG. 5, for example. In certain embodiments, analyte sensor 808 may differ at least in part from analyte sensor 530, depending on the context and / or application in which analyte sensor 530 and / or 808 may be used. Measuring device 810 may be used to apply a bias to analyte sensor 808 and / or to gather information from analyte sensor 808 that may be used to calculate the level of analyte in a host in which analyte sensor 808 is implanted.

[0148] In addition, the circuit 800 may include a capacitive element 834 and, optionally, a resistive element 832. The circuit 800 may also include a detection circuit 802, which in some cases may use or include, for example, an amplification element (e.g., a comparator). In addition, the circuit 800 may include one or more of a reference voltage 804, a reference voltage 818, and a driver circuit 806, which may be, for example, a clock-based driver. It should be understood that one or more of the reference voltages 804 and 818 may be substituted for other reference signals. It should also be understood that the driver circuit 806 may be driven by a signal other than a clock signal.

[0149] In an embodiment, the current-based actuation approach for the analyte sensor system 308 may be implemented using a circuit similar to the circuit 800 illustrated in FIG. 8A. However, certain modifications may be made in connection with some such embodiments. For example, the switch element 812 may not be present in the circuit 800 or may be, for example, bypassed or shorted. The switch element 814 may also be absent or may be effectively removed from the circuit 800 and / or placed in a high impedance or open circuit state. In such a case, the resistive element 832 may also be effectively removed from the circuit 800. It should be understood that other means may be used to effectively remove and / or bypass the resistive element 832. In an embodiment, the implantation of the analyte sensor 808 may still be determined / monitored based on detecting a particular (e.g., sufficient) current flow(s) between the first terminal 828 and the second terminal 830 of the analyte sensor 808.

[0150] Exemplary features of such modified or similar versions of circuit 800 are now provided as follows: The measuring device 810 may apply a potential (e.g., a substantially continuous voltage) between terminals 828 and 830 of the analyte sensor 830. For example, terminal 828 may be placed at a higher potential than terminal 830 such that current flow through the analyte sensor 808 may be provided via terminal 824 of the measuring device 810 (e.g., a potentiostat in some cases). In addition, for example, terminal 826 of the measuring device 810 and terminal 830 of the analyte sensor 808 may be coupled to one another and / or to a current-to-voltage conversion circuit.

[0151] In an embodiment, the current-to-voltage conversion circuit may include a capacitive element 834 that may be coupled at a first end to the terminals 826 and 830 and at a second end to a reference voltage 818 (e.g., ground). The first end of the capacitive element may also be coupled to a switching element 816. The switching element 816 may be driven by a driver circuit 806, which may include and / or use a clock-based or other signal type driver. The switching element 816 may thus alternately couple and decouple the terminals 826 and 830 to the reference voltage 818. The terminals 826 and 830 may be periodically coupled and decoupled to the reference voltage 818 according to a configurable, programmable, adaptable, and / or variable interval / frequency (e.g., 10 Hz). In some cases, the driver circuit 806 may make the coupling / decoupling of the terminals 826 and 830 to / from the reference voltage 818 non-periodic, asynchronous, and / or event-driven.

[0152] In one example, when the switch element 816 is placed in a higher impedance state or open, for example, at a first time, the terminals 826 and 830 may be decoupled or isolated (e.g., floating) from the reference voltage 818. Thus, the current flowing through the capacitance of the analyte sensor 808 may be effectively delivered to the capacitive element 834 as a charging current. This charging current may generate a potential across the capacitive element 834. When the switch element 816 is placed in a lower impedance or conductive state or closed, for example, at a second time, the terminals 826 and 830 may, in some cases, be directly connected or coupled to the reference voltage 818 (e.g., ground). In this configuration, any charge that may accumulate in the capacitive element 834 may be at least substantially discharged (e.g., to ground) such that the potential that may be generated across the capacitive element 834 may be returned / reset to at least near the potential of the reference voltage 818 (e.g., ground or 0V). Thus, in this example, when current flows through the capacitance of the analyte sensor 808 due to the action of the switch element 816, the resulting voltage signal waveform that may be present at terminals 826 and 830 may represent a series of voltage pulses (e.g., the voltage across the capacitive element 834 as a function of time), and such pulses may be proportional to the magnitude of the current through the capacitance of the analyte sensor 808.

[0153] Continuing with the example, in circuit 800, an input 822 of a detection circuit 802 (e.g., a voltage detection circuit that may be implemented as an amplification element, a comparator, other circuitry, etc.) may be coupled to terminals 826 and 830. In an embodiment, the detection circuit 802 is operable to compare a voltage across a capacitive element 834 to a reference voltage 804, which may be configurable, programmable, variable, adaptable, etc. The detection circuit 802 may be further operable to generate an output 836 that may be used to, for example, trigger actuation of the analyte sensor 308 when a particular condition or conditions is achieved (e.g., when the voltage across the capacitive element 834 is above, below, or within a range of the reference voltage 804, exhibits a specific trend, etc.). It should be noted that the reference voltage 804 may be configured based on a calibration, may be set according to a predetermined value / characteristic, and / or may be configured based on the circumstances or environmental conditions experienced by the analyte sensor system 308 in the field. Additionally, the detection circuit 802 may include and / or use configurable digital logic circuitry (not shown in FIG. 8A ) operable to count and / or otherwise characterize or measure a number of sequential voltage pulses that may meet (e.g., reach or exceed) a threshold. For example, if the number and / or characteristics of the measured / monitored pulses meet a configurable condition (e.g., a threshold number / magnitude), the output 836 may indicate that the analyte sensor system 308 should operate or cause or trigger to exit a lower power state.

[0154] However, in certain cases, the above examples may be more particularly suited for use in conjunction with a particular electrical model of the analyte sensor 808. For example, the above example circuit may be more suited to an implementation in which the analyte sensor 808 is modeled as a substantially or purely resistive load between the terminals 828 and 830 of the analyte sensor 808. However, in certain cases, this substantially resistive load may not be an approximate representation of the analyte sensor 808. By way of illustration, in the case of a substantially or purely resistive load, the voltage pulse that may develop across the capacitive element 834 as a result of the charging current may be of substantially constant amplitude for a given substantially constant current. Thus, the amplitude of the voltage pulse may increase proportionally with an increase in current.

[0155] However, as described above in connection with FIG. 7A, in embodiments, the electrical behavior of the analyte sensor 808 may not be accurately modeled by a substantially or purely resistive load. Instead, it may be more accurate to electrically model the analyte sensor 808 using a more complex passive circuit model that includes both capacitors and resistors, and may include other elements, for example, as illustrated in FIG. 7A. For example, if the relatively large capacitance Cdouble layer 718 of the analyte sensor 808 is included in the electrical model that may be used, the circuit 800 may operate differently when the terminals 828 and 830 of the analyte sensor 808 are initially connected into the circuit 800. In some cases, the difference may be significant or discernible. By way of illustration, instead of a constant amplitude voltage pulse sequence or train that may result when a resistive model / load is used (e.g., as described in connection with the example above), the waveform characteristics of the voltage across the capacitive element 834 may be substantially influenced (and in some cases dominated) by an initial inrush of charging current that may flow through the capacitance of the analyte sensor 808. This may result in (e.g., a series of) voltage pulses having an initial larger amplitude followed by a subsequent decreasing amplitude. The amplitude may decrease rapidly in some cases, for example, substantially according to an exponential decay that may be associated with the resistance / capacitance (RC) characteristics of the electrical equivalent model of the analyte sensor 808 illustrated by way of example in FIG. 7A. Reference is now made to FIG. 8B by way of example, which will be discussed in more detail below. As illustrated in FIG. 8B, for example, pulses that may be included in waveform 870 exhibit an exponential decay during period 845. However, it should be understood that if a resistive model is used for the analyte sensor 808, this decay may not be present, and instead, the pulses of waveform 870 may be relatively constant in amplitude.

[0156] Furthermore, if the capacitance of the analyte sensor 808 is charged and the current flow is primarily due to the steady-state current, the operation of the current-voltage circuit may remain significantly affected by the presence of the charged capacitor. For example, if a more complex electrical model is used, the amplitude of the residual voltage pulse that may be measurable across the capacitive element 834 for a given steady-state current may be meaningfully lower than the equivalent steady-state current that exists under a resistive load electrical model of the analyte sensor 808. Furthermore, the proportional difference in the magnitude of the corresponding voltage waveforms for the two different currents may no longer be sufficiently distinguished by the detection circuit 802 under normal circumstances. For example, the detection circuit 802 may not be able to accurately detect threshold crossings, etc., due to the relatively small or reduced difference in steady-state voltage pulse amplitude that may result when the electrical model of FIG. 7A is used.

[0157] In view of the above, it should therefore be appreciated that the exemplary configuration of the circuit 800 described above may generate a steady state current that may not result in a voltage pulse waveform of sufficient magnitude for detection or differentiation by the detection circuit 802. Thus, this exemplary configuration of the circuit 800 may not be conducive to accurate and robust operation of the analyte sensor system 308. For example, there may only be a single or a few opportunities to generate a sufficient voltage waveform that may be more easily / accurately / reliably detected by the detection circuit 802. For example, an initial relatively large voltage pulse that may result from an initial inrush of charging current may provide only a single detection event. Also, if this initial relatively large pulse or pulses is not detected by the detection circuit 802 or the analyte sensor system 308 does not operate as a result of the initial pulse(s) (e.g., because the analyte sensor 808 may not be sufficiently hydrated upon connection to the circuit 800), then the circuit 800 may not have another sufficiently detectable opportunity to detect / assess the implantation of the analyte sensor 808.

[0158] Accordingly, embodiments of the present disclosure include configurations of circuit 800 that are resettable by circuit components such as switches and other elements. For example, with further reference to FIG. 8A, circuit 800 may include switch elements 812 and 814. Switch elements 812, 814, and 816 may be implemented using electrical components including discrete or integrated components such as transistors or other passive / active devices (e.g., FET switches, etc.). As discussed in further detail below, switch elements 812 and 814 may be complementary such that when one switch element is closed, the other may be open, and vice versa. Switch elements 812 and 814 may be controlled using a clock or other signal driver, and in some cases, this clock may be derived from a clock or other source / drive signal used for driver circuit 806. In embodiments, switch elements 812 and 814 may be controlled by a clock or other source having a lower frequency than the clock or other source that may be used for driver circuit 806. For example, the (e.g., clock) frequency of switch elements 812 and 814 may be a fraction of the (e.g., clock) frequency of switching element 816, and the fractional value that may be used may be configurable, programmable, adaptable, and / or variable. Examples / options of fractions may include 1 / 10, 1 / 20, 1 / 40, 1 / 80, etc., in some cases. Thus, for each of these examples / options, switch elements 812 and 814 may change state every 10, 20, 40, or 80 cycles of the clock of switch element 816. Other ratios and relationships that may be established between driver circuit 806 and control of switch elements 812 and 814 will be understood upon review of this disclosure.

[0159] The output 836 of the detection circuit 802 may be coupled, for example, to the processor 535 of the analyte sensor system 308 such that the output 836 may be used to activate or trigger the analyte sensor system 308. The circuit 800 may be implemented within or in conjunction with the actuation detection circuit 520. If the circuit 800 is implemented as or as part of the actuation detection circuit 520, the output 836 may be coupled to the processor 535 such that the processor 535 may be used to cause or trigger the analyte sensor system 308 to wake up or exit a lower power state when signaled to do so. As mentioned above, the analyte sensor 808 may include a first terminal 828 and a second terminal 830. The detection circuit 802 may include a reference terminal 820 and an input terminal 822. The measurement device 810 may include a first terminal 824 and a second terminal 826.

[0160] As mentioned, the circuit 800 may be used to control the operation of the analyte sensor system 308. The detection circuit 802 may indicate whether a signal at the input terminal 822 achieves one or more conditions. For example, the conditions may be or include one or more threshold voltages that may be set using a reference voltage(s) 804 applied to a reference terminal(s) 820 of the detection circuit 802. The voltage(s) at the input terminal(s) 822 may indicate a current that may flow between the first terminal 828 and the second terminal 830 of the analyte sensor 808 (e.g., as described above, a circuit element of the circuit 800 including a capacitive element 834 may be used to effectively convert a current through the analyte sensor 808 into a voltage). For example, the condition(s) may be, use and / or include a threshold that may be programmable, adaptable, variable, and / or configurable, etc.

[0161] In certain examples, the condition(s) may be configured such that the condition(s) may be achieved if the voltage(s) of one or more signals provided at the input terminal 822 indicate a current that may flow between the first terminal 828 and the second terminal 830 of the analyte sensor 808 when the analyte sensor 808 is implanted in a host, or under other conditions. In such a case, the output(s) 836 of the detection circuit 802 may be used to trigger the analyte sensor system 308 to exit the lower power state by indicating that this signal(s) at the input terminal 822 satisfies the condition(s) (e.g., depending on the level(s) of the output signal(s) 836). For example, in some cases, the output(s) 836 of the detection circuit 802 may include a binary level, multiple discrete levels, and / or continuous or substantially continuous or analog values ​​that may be used to trigger actuation of the analyte sensor system 308 into one or more triggered or active states. In some cases, the state that the analyte sensor system 308 transitions to may depend on a characteristic (e.g., level, trend, etc.) of the output 836. In embodiments, as discussed further in connection with FIG. 8B , the condition(s) may be configured such that the condition(s) is achieved when a certain number of voltage pulses meet (e.g., reach or exceed) a threshold(s) or when a certain number and set of voltage pulses exceed the threshold(s).

[0162] The switch element 812 may be used to couple or decouple a first terminal 828 of the analyte sensor 808 to / from a first terminal 824 of the measuring device 810 (e.g., a potentiostat). The switch element 814 may be used to couple or decouple a first terminal 828 of the analyte sensor 808 to / from (optionally via a resistive element 832) an input terminal 822 of the detection circuit 802. The input terminal 822 of the detection circuit 802 may be coupled to a second terminal 830 of the analyte sensor 808 and to a second terminal 826 of the measuring device 810.

[0163] At a first time point, the switch element 812 may be closed or placed in a conductive state, coupling a first terminal 828 of the analyte sensor 808 to a first terminal 824 of the measuring device 810. The switch element 814 may be open or placed in a high impedance state at this time, isolating an input terminal 822 of the detection circuit 802 from the first terminal 828 of the analyte sensor 808. Thus, at a first time point, the measuring device 810 may be used in connection with gathering information that may be used to calculate a level of an analyte in a host. Additionally, a voltage waveform generated using the circuit 800 (e.g., as mentioned above), and in particular using a charging current that may flow through the capacitance of the analyte sensor 808, may be provided to the terminal 822 and monitored and compared to a reference voltage 804 using the detection circuit 802 (e.g., which may be or may include an amplification element and / or a comparator or other circuit).

[0164] At a second time point, the switch element 812 may be open or set to a high impedance state, thus isolating the first terminal 828 of the analyte sensor 808 from the first terminal 824 of the measurement device 810. The switch element 814 may be closed or set to a low impedance or conductive state at this point, thus coupling the second terminal 830 of the analyte sensor 808 to the first terminal 828 of the analyte sensor 808 (in some cases, optionally via a resistive element 832). This reduces or possibly eliminates the potential that exists across the analyte sensor 808, and the switching action of the driver 806 and the switch element 816 may be used to at least substantially discharge the accumulated charge on the capacitance of the analyte sensor 808 (see, e.g., FIG. 7A ) to create a conductive path to the reference voltage 818. As mentioned, resistive element 832 may optionally be used to limit the current that may flow through switch elements 814 and / or 816 when switch elements 814 and / or 816 are closed or placed in a conductive or low impedance state.

[0165] The capacitive element 834 may be coupled between the input terminal 822 of the detection circuit 802 (shown in this example as being coupled to the second terminal 830 of the analyte sensor 808) and a voltage reference 818 (e.g., ground). The switch element 816 may be driven by or otherwise obtained as an input by a signal (e.g., a clock or other signal) from the driver circuit 806 such that the switch element 816 may periodically couple the input terminal 822 of the detection circuit 802 to the reference 818. For example, if the reference voltage 818 is ground, this may at least substantially discharge the capacitive element 834, as further mentioned / discussed in connection with FIG. 8B . As noted, the capacitive element 834 may be used in conjunction with the driver circuit 806 and / or the switch element 816 to implement a current-to-voltage circuit. The current-to-voltage circuit may be operable to convert a current that may flow through the analyte sensor 808 into a voltage (e.g., a waveform) that can be measured or otherwise characterized using the detection circuit 802 in connection with determining whether a threshold / condition has been reached or satisfied, as mentioned above, and further in connection with activating and / or triggering the analyte sensor system 308 to change states.

[0166] In an embodiment, the switch elements 812 and 814 may be driven by a common signal that may be inverted for either the switch element 812 or the switch element 814. Alternatively, the switch elements 812 and 814 may be driven by a common signal, but the devices used for the switches 812 and 814 may have opposite polarities. For example, in an embodiment, the switch elements 812 and 814 may be driven such that the switch elements 812 and 814 are configured to be in opposite (e.g., impedance) states at a given time. Thus, the switch elements 812 and 814 may be configured such that, for the most part, when the switch element 812 is closed, the switch element 814 will be open, and vice versa. Configured in this manner, the switch elements 812 and 814 may be used to at least substantially discharge a capacitance associated with the analyte sensor 808. Thus, the initial inrush of current through the capacitance of the analyte sensor 808 that may normally be associated with implantation of the analyte sensor 808 within the body of a host can be substantially reproduced and used to generate an additional voltage pulse that can be monitored for purposes of actuating and / or causing the analyte sensor system 308 to exit a lower power state. Thus, in circumstances where the current rush resulting from implantation of the analyte sensor 808 does not trigger actuation, switch elements 812 and 814 can be used to essentially reset the circuit 800 such that another monitorable current rush occurs that may trigger actuation of the analyte sensor system 308.

[0167] Additionally / alternatively, to allow for flexibility, adjustment, configuration, and / or optimization, the timing of controlling the switch elements 812 and 814 to be in different states may be predetermined, programmable, adaptable, variable, and / or configurable such that the switch elements 812 and / or 814 may be placed in a particular state / mode according to various durations / intervals / frequencies / etc., and / or duty cycles, etc. Such timing control may be implemented using and / or derived from the driver circuit 806 such that, for example, every given number of cycles of the driver circuit 806, the state of the switch elements 812 and 814 may change and / or be maintained for a selectable / controllable duration.

[0168] 8B shows an example plot of a signal (e.g., voltage, current, etc.) of an analyte sensor 808 according to an embodiment of the present disclosure. Waveforms 870 and 880 may represent a signal (e.g., voltage, current, etc.) 840 as a function of time 842 (e.g., in seconds), such a signal may be a signal that may be present on or provided to an input terminal 822 of a detection circuit 802 in circuit 800 (see, for example, FIG. 8A ). A reference voltage 848 may be set, as described above, such that an output 836 of the detection circuit 802 may be used to trigger operation of the analyte sensor system 308 when a voltage or other signal present on the input terminal 822 of the detection circuit 802 reaches, exceeds, or crosses the reference voltage 848. 8B, during the time between the end of waveform 870 and the beginning of waveform 880, the signal (e.g., voltage) on input terminal 822 of detection circuit 802 may have been at least substantially discharged or reset by, among other things, closing switch element 814 and / or switch element 816. Resetting the voltage across analyte sensor 808 may enable circuit 800 to monitor for additional detection events in which the voltage on input terminal 822 may cross, reach, or exceed reference voltage 848.

[0169] 8B, the waveform 870 may include pulses 844a, 844b, and 844c, and may include additional pulses (including pulses not explicitly shown) as illustrated. As a non-limiting example, the driver circuit 806 may provide a clock (e.g., a square wave, a sine wave, etc.) or other signal for driving the switch element 816. A period of the clock signal may be considered the interval between each of the pulses 844a, 844b, and 844c. In certain examples, the driver circuit 806 may provide a non-periodic, asynchronous, and / or event-driven signal for controlling the operation of the switch element 816.

[0170] As a non-limiting example, the waveform 870 may have a duration of a particular period 845, which may be approximately 1 second in some cases, and the period of the clock signal from the driver circuit 806 may be approximately 100 milliseconds. As further shown, after an initial current rush and corresponding (e.g., voltage) pulse 844a of the waveform 870, which may result in association with implantation of the analyte sensor 808 in a host, each successive pulse 844b, 844c, etc. may decrease in amplitude according to a decay profile that may be associated, for example, with the effective time constant of the analyte sensor 808 (e.g., an RC time constant, as described above). Thus, as described above, the switch elements 812 and 814 may be used to generally reproduce the initial current rush used to form a pulse (e.g., pulse 844a) having a particular magnitude. This is illustrated by waveform 880, which may include, for example, pulses 846a, 846b, 846c, etc.

[0171] When switch elements 812 and 814 are set in the manner described above, waveform 870 may drop to or near ground or another reference voltage, as represented by period 855. In an embodiment, period 855 may be approximately 1 second (e.g., or any other time sufficient and / or long enough to substantially and / or completely discharge the capacitance of analyte sensor 808), after which waveform 880 and pulse 846a may be measured according to the state of switch elements 812 and 814. Waveform 880 may then be monitored in the manner described above to activate analyte sensor system 308.

[0172] Many variations are contemplated in connection with the present disclosure regarding one or more conditions that may be used to activate the analyte sensor system 308 in connection with the circuit 800. For example, a single pulse, such as pulse 844a, reaching, exceeding, and / or crossing threshold 848, or otherwise meeting a condition, may trigger activation of the analyte sensor system 308. In embodiments, a predefined number of pulses 844a, 844b, 844c reaching, exceeding, and / or crossing threshold 848, or otherwise meeting a condition may trigger activation. In some cases, a specific number of pulses from two or more waveforms (e.g., waveforms 870, 880, etc.), or a different respective number of pulses for each waveform 870, 880 (e.g., 844a, 844b, etc. and 846a, 846b, etc.) may be used to trigger activation. In certain examples, if the number of pulses from waveform 870 that achieve a condition does not result in actuation, one or more pulses from waveform 880 may be monitored for actuation. In some cases, a certain number of pulses that exceed threshold 848 by a certain amount may trigger actuation of analyte sensor system 308. In embodiments, if a first condition is not achieved in conjunction with detection circuitry that measures pulses of waveform 870, a second (e.g., modified) condition may be used to monitor pulses of waveform 880.

[0173] In embodiments, if the analyte sensor system 308 is actuated and / or triggered to exit a lower power state in response to the waveform 870, then in certain cases the waveform 880 may not need to be generated. In other cases, more than one waveform 870, 880, etc. may be used for actuation purposes, and subsequent waveforms other than the waveforms 870, 880 (not shown in FIG. 8B ) may not need to be generated. In some cases, if the analyte sensor 308 is not actuated in response to at least one of the waveforms 870, 880, etc., additional waveforms may be generated continuously. In embodiments, after a configurable number of waveforms have been generated without the analyte sensor system 308 being actuated, the waveform generation may be at least temporarily suspended, including for a predetermined, configurable, and / or event-based time, in some cases. Thus, in certain embodiments, the ability to essentially reset the circuit 800 may enable a more robust actuation detection scheme, as discussed above / herein.

[0174] In addition, with further reference to FIG. 8B, in certain embodiments, the duration of each of the periods 845, 855, and 865 may be jointly or independently varied. For example, the periods 845 and 865 may be considered active (e.g., default) states, and the period 855 may be considered a reset or inactive state with respect to generating pulses. In examples, the duration or duty cycle of the active state (e.g., during periods 845 and / or 865) and the reset state (e.g., during period 855) may be configurable, including depending on the circumstances. In some cases, the duty cycle may be configured to be offset such that the circuit 800 may remain in the reset state longer than the active state, or vice versa.

[0175] For example, in some circumstances, it may be beneficial to increase the duration of the reset cycle compared to the active state. This may better provide the capacitance of the analyte sensor 808 with sufficient time to more fully discharge between two consecutive active cycles (e.g., between the end of period 845 and the beginning of period 865). This may facilitate a more consistent, repeatable, and / or accurately detectable initial charging current response and corresponding voltage pulse waveform. Note that in light of FIG. 8B, any number of waveforms 870, 880 may be repeated. The length of the reset state between various such waveforms may vary, such as between two sets of waveforms associated with the active state. In some cases, the length of the reset state(s) may be configurable, variable, adaptive, and / or programmable, for example, the length may change in response to the detection circuit 802 not triggering actuation of the analyte sensor system 308 after a certain amount of time has passed and / or in the presence of other conditions (e.g., accelerometer or hydration-related conditions) that may be monitored using the analyte sensor system 308 as described herein. Additionally, the length of the active (or reset) state may vary from active state to active state (or reset state to reset state), or on any other basis.

[0176] In one example, the circuit 800 may be in an active state when the switch element 812 is closed and the switch element 814 is open. The circuit 800 may be in a reset state when the switch element 814 is closed and the switch element 812 is open. In the reset state, in this example, the analyte sensor 808 may be disconnected / isolated from the terminal 824. Thus, there may be no power provided to the analyte sensor 808. At the same time, when the switch element 814 is closed, it may connect / couple the terminals 828 and 830 to each other, optionally via the resistive element 832 (which may function, for example, as a current limiter). In this manner, charge that may accumulate on the capacitance of the analyte sensor 808 may be at least substantially discharged by a path that may be created by the switch element 814 and the optional resistive element 832 in conjunction with the continued / progressive toggling of the switch element 816 that may be used to couple the terminal 828 to the reference voltage 818 (e.g., ground) via this path. When terminal 824 of measuring device 810 is isolated from the remaining elements of circuit 800, there is no new source of charging current for capacitive element 834, so that any charge that may have accumulated in capacitive element 834 may also be at least substantially discharged under these conditions (e.g., during this period).

[0177] Advantageously, the circuit 800, when used in conjunction with a circuit model illustrated in, for example, FIG. 7A, may result in a repeatable / consistent and / or controllable / configurable chance to generate a voltage waveform(s) (e.g., see FIG. 8B, waveforms 870 and 880) that is sufficiently, reliably, and / or accurately detectable using the detection circuit 802. If an initial current rush is not detected by the analyte system 308 using the circuit 800 due to some circumstances that may exist (e.g., the analyte sensor 808 is not sufficiently hydrated, etc.), the circuit 800 may allow additional attempts / chance for the detection circuit 802 to detect the analyte sensor 808 during a subsequent active cycle following a reset cycle(s), which may be affected in the manner described above.

[0178] 8C is an operational flow diagram illustrating a method 850 for controlling operation of the analyte sensor system 308 according to an embodiment of the present disclosure. Although the method 850 is described below with reference to the particular schematic elements shown and discussed in connection with FIG. 8A, the method 850 should not be understood to be necessarily limited to such configurations / elements. The operations of the method 850 may be used in connection with a robust actuation scheme for the analyte sensor system 308.

[0179] At operation 852, the method 850 may involve the detection circuit 802 monitoring the analyte sensor 808, e.g., monitoring a voltage present at an input terminal 822 of the detection unit 802, which may be coupled to a second terminal 830 of the analyte sensor 808. The analyte sensor 808 may be coupled to a measurement device 810 (e.g., a potentiostat or other measurement circuit) to monitor an electrical characteristic of the analyte sensor 808. The method 850 may optionally include, at operation 854, coupling the input terminal 822 of the detection circuit 802 to a reference voltage 818 (e.g., ground) using a switch element 816. The switch element 816 may be controlled and / or driven using one or more signals from a driver circuit 806 (e.g., a clock or other signal driver).

[0180] At operation 860, the method 850 may involve determining whether the measurement of the input terminal 822 of the detection circuit 802 satisfies one or more conditions. For example, such conditions may include whether the input terminal 822 of the detection circuit 802 reaches, exceeds, or crosses a threshold voltage (e.g., referring to FIG. 8B as an example, threshold voltage 848), or achieves another characteristic, such as meeting threshold voltage 848 several or many times over a number of different time periods (e.g., as described above in connection with FIG. 8B). In an embodiment, the condition / characteristic may include a consistent frequency of positive determinations that the input terminal 822 of the detection circuit 802 presents a voltage that reaches, exceeds, or crosses a threshold voltage, or achieves another condition over a sustained period of time, and thus may help ensure that a condition is not reached based on anomalies.

[0181] As an example, the operation 860 may entail comparing the voltage at the input terminal 822 of the detection circuit to a threshold value (e.g., see, for example, FIG. 8A , reference voltage 804). For example, the voltage at the input terminal 822 of the detection circuit 802 may be indicative of a current that may flow between a first terminal 828 and a second terminal 830 of the analyte sensor 808. As discussed above, in certain examples, the detection circuit 802 may use and / or detect an amplification element, a comparator, etc. that may be used to detect whether the measured voltage across the terminals 828 and 830 of the analyte sensor 808 may achieve or meet (e.g., exceed) a characteristic. In an embodiment, the characteristic (e.g., threshold voltage) may be set using a reference voltage 804 that may be applied to a reference terminal 820 of the detection circuit 802.

[0182] If the one or more conditions are met, the method 850 may further include triggering the analyte sensor system 308 to exit the lower power state at operation 862. For example, the analyte sensor system 308 may be triggered to exit the lower power state as a result of the one or more conditions being met, as determined using the circuit 800 (see, for example, FIG. 8A ) and indicated by the output 836. However, if the one or more conditions are not met, the method 850 may include operation 858, which involves controlling the switch elements 812 and 814 to at least substantially discharge a capacitance associated with the analyte sensor 808 (e.g., as described above in connection with FIGS. 8A and 8B ). The method 850 may then involve returning to operation 852 while the analyte sensor system 308 remains in the lower power state.

[0183] Thus, operation 858 may involve causing switch elements 812 and 814 to periodically at least substantially discharge the capacitance of the analyte sensor 808, where at a first time point, switch 812 may be effectively closed or in a low impedance state and thus used to couple the first terminal 828 of the analyte sensor 808 to the measuring device 810. And at a second time point, switch element 812 may be effectively opened or in a high impedance state to largely isolate the first terminal 828 of the analyte sensor 808 from the measuring device 810, while switch element 814 may couple the first terminal 828 and the second terminal 830 of the analyte sensor 808 to each other (e.g., via resistive element 834, which in some cases may be used as a current limiter) to at least substantially discharge the capacitance of the analyte sensor 808 and / or the circuit 800. As discussed above, operation 858 effectively resets the circuit 800 to a measurement state such that the current that may flow through the capacitance of the analyte sensor 808 may generally be repeated, thus allowing for another detectable event and providing a more robust actuation detection mechanism for the analyte sensor system 308.

[0184] 5, another approach that may be used to power the analyte sensor system 308 is voltage generation. In an embodiment, the transcutaneous portion of the analyte sensor 530 may be used to electrochemically generate a small voltage. That is, the host's body into which the analyte sensor 530 is inserted may be used as an electrolytic medium to enable a chemical reaction that produces electrical energy, as in a battery. For example, electrolytes in the body may be used to transfer electrons in a chemical reaction to generate a detectable voltage that may be monitored and used to trigger the analyte sensor system 308 to exit a lower power state.

[0185] Using Other Signals to Exit Lower Power States According to an embodiment, an additional aspect of the disclosure involves using a secondary sensor or means other than the analyte sensor 530 (see, for example, FIG. 5 ) for purposes of operation in a pre-connected analyte sensor system 308. Various events may be detectable by the analyte sensor system 308, such events being indicative of implantation of the analyte sensor 530. Examples include separation of the analyte sensor system 308 from an applicator, separation of the analyte sensor system 308 from packaging, and detecting proximity of the analyte sensor system 308 to a host or user. These events or phase changes may be detected using a number of different sensor types, as described below.

[0186] A first category of sensor types that may be used to detect implantation-related events involves the actuation detection circuit 520 using one or more signals generated by components included in the analyte sensor system 308 without the use of additional components. This category of sensors is advantageous because they can be built into the analyte sensor system 308, therefore being of low cost and complexity, and typically not requiring user interaction.

[0187] One example of an approach in the first category of sensor types uses a proximity sensor to actuate the analyte sensor system 308. Such a sensor may detect or estimate distance and / or change in distance between the analyte sensor system 308 and a reference point, which may be the host, an applicator of the analyte sensor system 308, packaging of the analyte sensor system 308, or another object. With reference to FIG. 5, the proximity sensor may be implemented using one or more of an actuation detection circuit 520 and an actuation detection component 545.

[0188] In an embodiment, the proximity sensor may be implemented using capacitive sensing. For example, the actuation detection circuit 520 may include a capacitive coupling circuit capable of detecting and / or measuring conductive objects or other objects having a dielectric constant different from air. In this regard, two capacitive sensing types may be used.

[0189] A first type of capacitive sensing may involve detecting mutual capacitance between the capacitive coupling circuitry and another object. For example, the other object, such as a host or user's finger, a host or user's skin, a base plate of an applicator, or any other object, may alter the mutual coupling between the electrodes that may be included in the actuation detection component 545. The actuation detection component 545 may communicate this alteration or change in mutual coupling to the actuation detection circuitry 520 to trigger an actuation event that may cause the analyte sensor system 308 to exit the lower power state. Note that in an embodiment, the monitoring of the capacitive coupling occurs while the analyte sensor system 308 is in the lower power state.

[0190] A second type of capacitive sensing may involve self-capacitance or absolute capacitance, where an object such as a user's finger or skin or an applicator base plate (see, e.g., FIGS. 6A and 6B, described in more detail below) may increase the parasitic capacitance of the capacitive sensor to ground, increasing the capacitive load to the capacitive sensor of the actuation detection component 545. This capacitive load event may be communicated to the actuation detection circuit 520 to trigger an actuation event.

[0191] In an embodiment, the proximity sensor may be implemented using inductive sensing. A non-contact electronic proximity sensor may be implemented using inductive sensing. The sensor may be used to locate and detect metal and other conductive objects that may be located in one or more portions of the actuation detection component 545 in the applicator of the analyte sensor system 308. Now, refer to FIG. 6A and FIG. 6B by way of example. The inductive sensing based proximity sensor of the actuation detection component 545 may include an inductive loop. A current typically generates a magnetic field. When the magnetic field changes, the changing field may generate a current. The inductance of the loop may change due to the proximity of a metal object modifying the current flowing through the loop. The change in inductance may be detected using a sensing circuit that may be included in the actuation detection circuit 520 and / or the actuation detection component 545, and this change may be used to trigger the analyte sensor system 308 to exit a lower power state.

[0192] Another approach to implementing a proximity sensor is to use a magnetic detector and / or sensor. Thus, an embodiment of the actuation detection component 545 includes a magnet that may be located within the packaging of the analyte sensor system 308, within the applicator of the analyte sensor system 308 (see, e.g., FIGS. 6A and 6B), or on or within a display device utilized to interact with and / or display the analyte value of the user. The proximity sensor may be configured to trigger actuation of the analyte sensor 308 based on the presence or absence of a detected magnetic field (e.g., a Hall effect sensor, a reed switch, etc.). The presence or absence of the detected magnetic field may then be used to trigger the analyte sensor system 308 to exit a lower power state. More specifically, in some embodiments, the magnetic-based sensor may use a Hall effect, a reed switch, or other magnetic means for actuation purposes. For example, components (e.g., needle hub, spring, needle, or body of the applicator) in the applicator of the analyte sensor system 308 or on a display device configured to allow a user to interact with and / or view information related to the analyte sensor system 308 may be magnetized or may include magnets. Movement caused by deployment of the analyte sensor system 308, removal of the analyte sensor system 308 from the applicator, or movement of such a display device relative to the analyte sensor system 308 may trigger a magnetic-based sensor.

[0193] For example, a conductive flexible puck may be designed to contact a corresponding split connector in the analyte sensor system 308 when the analyte sensor system 308 is deployed. When the flexible puck contacts the split connector, a short circuit may be formed, causing the analyte sensor system 308 to activate after detecting the short circuit through impedance measurements or through the resulting connection to a power source (e.g., a battery). For example, a pull-up / pull-down circuit may be triggered using the puck. In another example, the processor 535 may monitor an interrupt signal from a reed switch or Hall effect switch, or the like, that may be generated when the switch is no longer in close enough proximity to a magnet, which may be located in the applicator of the analyte sensor system 308 or in its packaging.

[0194] 6D and 6E show top views of respective exemplary embodiments of split connectors 640, 650 of the analyte sensor electronics module 12 that may be included in the actuation detection component 545. FIG. 6D shows an exemplary embodiment of split connector 640 having a generally axisymmetric layout, where the connector 640 is split into two semicircular partial contacts 642a and 642b. FIG. 6E shows a top view of an exemplary embodiment of split connector 650 having a generally concentric (coaxial) design, where a first partial contact 652a is surrounded by a second partial contact 652b. A space may be provided between the contacts 652a and 652b to insulate the contacts 652a and 652b from one another.

[0195] In some embodiments, while in the lower power mode, the analyte sensor system 308 may monitor an interrupt signal from the reed switch. In embodiments, an interrupt signal may be sent from the reed switch when the switch is placed in a second state (e.g., open), which may occur when the magnet is no longer sufficiently close to the reed switch to maintain the reed switch in the first state. For example, a magnet may be placed near the actuation detection component 545 during manufacturing to maintain the analyte sensor system 308 in the lower power mode while the analyte sensor system 308 is within its packaging or container and / or within an applicator for the analyte sensor system 308. When it is desired to use the analyte sensor system 308 and implant the analyte sensor 530 into a user / host, the analyte sensor system 308 may be removed from the container and / or packaging, and the magnet may accordingly move from the vicinity of the actuation detection component 545, thus causing the analyte sensor system 308 to trigger actuation. For example, a reed switch, Hall effect switch, or the like, may be internal to the analyte sensor system 308 to cause the actuation detection component 545 to trigger the analyte sensor system 308 to exit a lower power state. Activation may occur, for example, when the analyte sensor system 308 is removed from its product packaging. The switch may also be activated when the analyte sensor system 308 is moved out of proximity to the applicator.

[0196] In some embodiments, an interrupt signal is generated and sent from the magnetic sensor, e.g., a reed switch, when a magnet is brought close enough to cause the magnetic sensor to change state. For example, a magnet (e.g., a thin 10-30 mil self-adhesive magnet or magnetic sticker) may be affixed to any of the display devices 110, 120, 130, and 140 illustrated in FIG. 1. In some implementations, when a user wishes to wake the analyte sensor system 308, e.g., to obtain one or more analyte concentration values ​​(e.g., glucose concentration values) on demand, the user may touch the analyte sensor system 308 with a magnet affixed to the display device or bring the magnet close enough to the analyte sensor system 308 so that the magnetic sensor changes state. In some embodiments, the magnetic sensor may be configured to distinguish between different relative motions, spatial orientations, and / or alignments of the magnet and / or the magnetic field of the magnet with respect to the magnetic sensor. For example, the magnet may include a multi-pole magnet, and / or the magnetic sensor may be configured to initiate or otherwise trigger a wake-up signal in response to the magnet or the magnet's magnetic field and a specific, predetermined relative motion and / or spatial orientation of the magnetic sensor and / or display device 110, 120, 130, 140. In response to a change in state of the magnetic sensor, a wake-up signal configured to cause the analyte sensor system 308 to wake up from a low power consumption mode may be triggered. Upon waking from a lower power consumption mode, the analyte sensor system 308 may be configured to initiate a wireless communication protocol (e.g., BLE) and / or power up an associated chip. The transceiver 510 may be configured to initiate advertising, for example, by transmitting one or more advertising packets. In some embodiments, the advertising packets may include one or more codes and / or patterns specific to a particular wake-up protocol. The display devices 110 , 120 , 130 , 140 can receive the advertising packets and transmit requests for analyte concentration values ​​to the transceiver 510 .The analyte sensor system 308 may be configured to transmit one or more analyte concentration values ​​to the display device 110, 120, 130, 140. Upon transmitting one or more analyte concentration values, the analyte sensor system 308 may be configured to cease transmitting advertising messages and revert to a lower power consumption mode. In response to receiving one or more analyte concentration values, the display device 110, 120, 130, 140 may be configured to play a short audio clip or sound indicating to a user that the analyte concentration value(s) have been received by the display device 110, 120, 130, 140. Such an embodiment may be advantageous for several reasons, including, but not limited to, very low cost of implementation, low impact on battery life, compatibility with any type of display device up to those that do not use a specific communication protocol, and providing a solution that has minimal impact on the aesthetics of the display device 110, 120, 130, 140.

[0197] In embodiments, acoustic and / or audio detection may be used to sense proximity between the analyte sensor system 308 and a reference point. For example, the actuation detection circuit 520 and / or actuation detection component 545 may include an ultrasonic or audio-based proximity sensor and one or more microphones and / or speakers that may detect relative movement between an object, such as an applicator or packing, and the analyte sensor system 308, for example, using the Doppler effect. The detected movement may then be used to trigger the analyte sensor system 308 to exit a lower power state. As an example, a shift in the frequency of an ultrasonic or audio signal may be detected using acoustic / audio detection that the analyte sensor system 308 is moving away from the applicator or packaging in a manner that indicates implantation has occurred or is about to occur. In some embodiments, a frequency shift may not be required for detection / actuation purposes. Rather, the presence or absence of audio / acoustic signaling may be used to trigger actuation of the analyte sensor system 308, or the presence of an audio / acoustic signal of a particular amplitude or characteristic may be used for actuation purposes.

[0198] A temperature-based detection approach may be utilized in addition to or instead of a proximity-based approach, as another example of an electromechanical approach in the first category of sensor types (e.g., without using components external to the analyte sensor system 308), where one or more temperature sensors may be coupled to a printed circuit board, chip, or the like. For example, the actuation detection component 545 may include such a temperature sensor that may use a thermistor, a thermocouple, or the like. The temperature sensor of the actuation detection component 545 may be implemented within the analyte sensor system 308 and / or external to the analyte sensor system 308.

[0199] The temperature sensor may be configured to detect temperature at a single location (e.g., a change in temperature or a comparison of temperature to a threshold) or at multiple locations to detect a temperature gradient (e.g., multiple temperature sensors can be utilized at different locations with known separation distances). In some cases, the temperature may be used to infer contact and / or proximity to a user's body. For example, a temperature approaching the normal temperature of a human body may indicate proximity to a user. The gradient measurement may be used to infer heating or cooling from a known direction and therefore, for example, the direction of movement of the analyte sensor system 308 or another object that emits heat (e.g., a host's body, etc.), or a direction of orientation toward or away from the human body. Thus, the detected temperature or temperature profile may be used to trigger the analyte sensor system 308 to exit a lower power state.

[0200] In an embodiment, the actuation detection circuit 520 and / or actuation detection component 545 may include one or more accelerometers or gyroscopes that may be used to monitor the movement and orientation of the analyte sensor system 308 and detect one or more events indicative of implantation of the analyte sensor 530. One such event may involve a relatively sudden increase in acceleration of the analyte sensor system 308 that may result, for example, from a spring-activated applicator mechanism that may be used in connection with implantation of the analyte sensor 530 (see, for example, FIGS. 6A and 6B). Another such event may include deceleration from the analyte sensor system 308 that may impact the user's skin surface (e.g., hitting the user during implantation). In an embodiment, both acceleration and deceleration events may be used to increase robustness, detect movement-related events, and / or trigger actuation of the analyte sensor system 308.

[0201] One potential concern with accelerometer-based and other deployment-based actuation methods is power usage. For example, the power usage involved in monitoring an accelerometer signal may be proportional to the sampling frequency used for monitoring. Because the insertion / implantation of the analyte sensor 10 typically occurs over a relatively short period of time (e.g., 30 milliseconds), a relatively high sampling frequency (e.g., 5 milliseconds) may be necessary to reliably detect the implantation. Such a relatively high sampling frequency may correspond to higher power consumption. Thus, embodiments of the present disclosure are directed to using accelerometers to accurately capture acceleration / deceleration and other motion-related events while maintaining power efficiency.

[0202] In an exemplary embodiment, the sampling frequency used to monitor the signal from the accelerometer or other means to detect deployment of the analyte sensor system 308 may be varied. For example, a lower sampling frequency may be used to monitor the accelerometer signal in a power efficient manner in response to events indicative of an upcoming deployment of the analyte sensor system 308. Such events may include, for example, a user unpacking the analyte sensor system 308, a user opening packaging associated with the analyte sensor system 308, and / or a user being present at a location / time typically associated with installation / deployment / implantation of the analyte sensor system 308 (e.g., at a hospital, clinic, the user's home, or other such location as may be determined using location services such as GPS, and / or at a particular time of day and / or day that the user prefers or typically deploys the analyte sensor system 308).

[0203] Additional events that may be used to indicate future deployment of the analyte sensor system 308 may be or include: (1) removal of an applicator safety mechanism, such as a safety card on the applicator (e.g., a plastic component that is removed from the applicator to enable triggering) or a frangible portion (e.g., a frangible portion on the applicator trigger that must be removed to enable triggering), (2) a push / force applied to the applicator (e.g., the applicator must be placed on a surface (e.g., a skin surface) with minimal force to enable triggering), (3) a breakage of a frangible member (e.g., similar to the safety ring on a plastic soda container), (4) a partial rotation of a threaded safety ring, (5) applying pressure to an integrated side trigger button, and / or (6) various other safety lock mechanisms. Another approach to varying the sampling frequency that may be used to monitor the accelerometer may involve tactile input obtained directly or indirectly from the user, which may be detected using the accelerometer (e.g., the user may tap the analyte sensor system 308 to transition to a higher sampling frequency). This will be discussed in more detail below.

[0204] The safety lock mechanism may be configured to be activated / triggered by the user, although in some embodiments a pre-activated system may also employ a safety lock mechanism, for example to prevent premature triggering or actuation of an already-activated spring.

[0205] These trigger events to the accelerometer or other actuation detection means may cause a transition in the sampling frequency used by the analyte sensor system 308 to monitor the output signal of the accelerometer or other actuation means from a relatively lower sampling frequency to one or more relatively higher sampling frequencies that can more reliably detect / capture motion triggers or other events that take place over a relatively short period of time, such as the implantation of the analyte sensor 530. By varying the sampling frequency, a lower amount of power may be used while still maintaining accurate event detection using the accelerometer-based or other approaches as described herein.

[0206] While the use of events associated with positive / positive motion is discussed above, it should also be appreciated that events associated with negative motion may be used to trigger actuation of the analyte sensor system 308 or to change the sampling frequency or frequencies that may be used to monitor the accelerometer. That is, lack of motion, orientation, or a particular location or type of location may be used to trigger a lower sampling frequency or frequencies. As an example, a lower sampling frequency may be used if the analyte sensor system 308 has been relatively immobile for an extended period of time or has been in the same position / orientation for a relatively extended period of time. As an additional example, a lower sampling frequency may be used if the analyte sensor system 308 is determined to be located at a storage facility (e.g., based on GPS, A-GPS, location detection, user check-in, or using other location services). This may allow for power savings without sacrificing accuracy of implant detection when conditions indicate that an implant is unlikely to have occurred.

[0207] 9 provides an example plot illustrating the operation of the analyte sensor system 308 in conjunction with an accelerometer-based or other detection scheme that employs a variable sampling frequency to reduce power consumption and / or accurately detect the implantation of the analyte sensor 530, while maintaining the ability to reliably operate the analyte sensor system 308 and avoid false wake-ups (e.g., for more reliable calculation of analyte values, etc.). For example, the accelerometer signal may be used at a power-efficient sampling frequency (e.g., 1 second, 2 seconds, 5 seconds, 30 seconds, 1 minute, greater than 1 minute, depending on the application) to detect events such as, but not limited to, unpacking or opening packaging, locating an installation area, safe removal of an applicator, and / or motion associated with an applicator trigger. Once detected, such events may be used to sample the accelerometer more frequently (e.g., 1000 ms, 500 ms, 250 ms, 100 ms, 50 ms, 10 ms, etc.), with higher frequencies allowing for more reliable capture of motion trigger events. Alternatively, or in addition, events involving a relative lack of movement or orientation may be detected and, in certain instances, such events may be used to trigger a lower sampling frequency.

[0208] Plot 900 represents one or more operating states of the analyte sensor system 308 plotted against time (e.g., seconds). For example, the one or more operating states may include an untriggered state and a triggered state of the analyte sensor system 308. The untriggered state may include or be, in various cases, an inactive or substantially inactive state, a lower power state, a sleep mode, and / or the like. At point 902 of plot 900, a measurement device (e.g., a potentiostat) that may be used in connection with the analyte sensor system 308 detecting an analyte in a host may respond to a particular input event. For example, when the analyte sensor system 308 is in an untriggered state, one or more electrodes of the analyte sensor 530 may be voltage biased and / or used to measure an analyte or gather information related to the analyte. It should also be understood that in certain embodiments, one or more electrodes of the analyte sensor 530 may not be biased during the untriggered state. For example, biasing of the electrodes may be greatly reduced or avoided during the untriggered state in some cases. This may be based on monitored environmental or other conditions, predetermined variables or settings, etc., as described herein.

[0209] At point 904, the analyte sensor system 308 is illustrated in a triggered state. The triggered state may be considered in various cases to be an active or substantially active state of the analyte sensor system 308. In an exemplary implementation of the triggered state of the analyte sensor system 308, the analyte sensor 530 may be voltage biased or otherwise measure / characterize an analyte using a measurement device. Additionally, the triggered state of the analyte sensor system 308 may cause other components of the analyte sensor system 308 to operate, e.g., the connection interface 505 may receive / transmit data, the processor 535 may perform various operations, etc. Region 910 of the plot 900 represents an example of a transition between the untriggered and triggered states of the analyte sensor system 308.

[0210] 9, plot 912 may represent an example of a signal that may be used in connection with changing the operational state / state versus time (e.g., seconds) of the analyte sensor system 308. The signal may be monitored (e.g., over time) and used to change or otherwise control the operational status / state of the analyte sensor system 308, one or more components of the analyte sensor system 308, and / or circuitry within the actuation detection circuit 520 of the analyte sensor system 308. For example, such components and / or circuitry may be used to monitor an output signal from an accelerometer or other actuation detection means, which may be used in connection with the actuation detection component 545.

[0211] In the time domain 916, for example, the signal may be at or relatively near the first value (e.g., a relatively lower value is illustrated in FIG. 9, but it should be understood that the first value may be a relatively higher value). Additionally or alternatively, the signal may include and / or be used to convey otherwise distinct values, trends, frequencies, slopes, gradients, etc., that may be observed / detected. For example, the first value, etc., may be compared / measured against other values / characteristics of the signal that may occur on an absolute or self-relative basis and / or in different time domains, such as those illustrated in plot 912. The first value, etc., of the signal may be used to indicate that the analyte sensor system 308, components of the analyte sensor system 308, and / or monitoring circuitry may be maintained in a non-triggered state.

[0212] And, for example, in the time domain 914, the signal may be at or relatively near the second value (e.g., in FIG. 9, a relatively higher value is illustrated, but it should be understood that the second value may be a relatively lower value). Additionally or alternatively, the signal may include and / or be used to convey otherwise distinct values, trends, frequencies, slopes, gradients, and / or the like that may be observed / detected. For example, the second value, etc. may be compared / measured against other values / characteristics of the signal that may occur on an absolute or self-relative basis and / or in different time domains, such as those illustrated in plot 912 in FIG. 9. The second value, etc., may be used alone or in combination with, for example, the first value and / or other variables / conditions to cause the analyte sensor system 308, one or more components of the analyte sensor system 308, and / or monitoring circuitry, for example, to keep the analyte sensor system 308, components of the analyte sensor system 308, and / or monitoring circuitry in a non-triggered state but more actively monitor an output signal from an accelerometer and / or other actuation detection means that may be used in connection with the actuation detection component 545.

[0213] FIG. 9 also illustrates that the plot 912 may include a sampling period 918 that may be used prior to the occurrence of the trigger 906. In response to the trigger 906, a sampling period 920 may be used that may be shorter than the sampling period 918 (e.g., and thus representing a higher sampling frequency). By way of example, the trigger 906 may be an acceleration / deceleration event associated with unpacking the analyte sensor system 308 or any other trigger event described herein. Using the shorter sampling period 920 may enable the monitoring circuitry to detect motion-based and / or other events associated with future, ongoing, or past implantation of the analyte sensor 530, represented here by the trigger 908 by way of example. In response to the trigger 908, the analyte sensor system 308, components of the analyte sensor system 308, the measurement device, and / or the monitoring circuitry transitioned from the untriggered state 902 through a transition region 910 to the triggered state 904. The trigger 908 may, for example, initiate a transition of the analyte sensor system 308 from a lower power state to a more active state.

[0214] In an embodiment, a wireless / antenna-based approach may be used to activate the analyte sensor system 308. For example, the activation detection component 545 may include a component such as an NFC or RFID tag, portions of which may be internal to the analyte sensor system 308 and / or portions of which may be external to the analyte sensor system 308, that may be placed in proximity to the analyte sensor system 308. By way of example, such a tag may be located in an applicator of the analyte sensor system 308 or in the packaging of the analyte sensor system 308 (see, e.g., FIGS. 6A and 6B). At regular intervals, the analyte sensor system 308 may interrogate the tag to establish a proximity relationship. For example, the analyte sensor system 308 may use a transmitter, which may be part of the transceiver 510, to send / receive pings or other messages / signals to / from the tag. If the analyte sensor system 308 does not receive a response to a ping or other message / signal, the lack of response may be used to indicate deployment of the analyte sensor system 308 (e.g., insertion of the analyte sensor 530) and thus a trigger to exit the lower power mode. In embodiments in which the analyte sensor system 308 continues to send ping messages after deployment, the analyte sensor system 308 may receive an input (e.g., via the GUI of the connected display device 310) indicating that deployment is occurring and, as a result, cease sending ping messages. In some cases, the tag may be an active component that pings the analyte sensor system 308 or an actuation detection component. In such cases, if the analyte sensor system 308 stops receiving pings from the tag, the lack of received ping messages may be used to indicate deployment of the analyte sensor system 308.

[0215] In an exemplary embodiment, during deployment of the analyte sensor system 308 or its removal from packaging, NFC or RFID may be used to detect an alteration in the proximity relationship between the analyte sensor system 308 and a reference point, such as packaging, and the alteration may be used to trigger the analyte sensor system 308 to exit a lower power state. The alteration in the proximity relationship may also be detected using measurements made by the transceiver 510, such as, for example, RSSI, or other channel measurements that may indicate proximity from a reference point. These measurements (e.g., RSSI) may be used to trigger the analyte sensor system 308 to exit a lower power state when an estimated distance between a reference location and the analyte sensor system 308 meets a condition, such as, for example, a particular threshold distance. Additionally, in certain embodiments, NFC may be used to provide a wake-up command (e.g., from one or more display devices) to the analyte sensor system 308 to activate the analyte sensor system 308. Alternatively, the absence of an NFC ping, or an NFC ping dropping below a certain power level, can be used to indicate a lack of proximity and therefore trigger operation of the analyte sensor system 308.

[0216] In other examples, the analyte sensor system 308 may utilize radio frequency echoes to trigger the analyte sensor system 308 to exit a lower power state. For example, the analyte sensor system 308 may use the transceiver 510 to intermittently emit an RF signal and monitor the echo for parameters that may be known (e.g., well characterized) for a given environment (e.g., within a packaging or applicator). Such parameters may include, by way of example, signal strength, Doppler, distance, density, and material. If the subsequent emission and resulting echo change, this may indicate a change in the environment that may be used to trigger actuation. Thus, an embodiment involves detecting environmental changes using radio waves to determine the range, angle, or speed of objects around the analyte sensor system 308 and characterize (e.g., changes) within the surrounding environment using the bounceback of the transmitted signal. For example, phase angles, etc. may be measured to characterize the surrounding environment. One example of RF emission may involve BLE (Bluetooth Low Energy). In one example, the one or more wireless sources may broadcast wireless signals from one or more unique locations. The wireless source(s) may be localized to one or more facilities or other locations where the analyte sensor system(s) 308 may be stored, or to a manufacturing location associated with the analyte sensor system(s) 308. In some examples, the wireless source(s) may be a BLE source or an RF source as described herein. In an embodiment, the analyte sensor system 308 (e.g., while located at a storage facility) may be configured to monitor or listen for broadcasted wireless signals or signal characteristics and determine whether a received broadcast signal characteristic (e.g., signal strength or other aspect) is above, below, or near a threshold. Based on the determination, the analyte sensor system 308 may or may not transition from a lower power / sleep mode to an active mode.For example, if the received signal characteristic is above a threshold (e.g., may indicate that the analyte sensor system 308 is still within the storage facility), the analyte sensor system 308 may remain in a lower power mode or a sleep / shelf mode. In another example, when the analyte sensor system 308 is moved to another location (e.g., to a patient's home or exam room, or farther away from the storage facility), the analyte sensor system 308 may determine that the monitored signal characteristic is below a threshold. Thus, the analyte sensor system 308 may then transition from the lower power mode to an active or operational mode.

[0217] In an embodiment, the actuation detection component 545 includes an air pressure sensor that may be used in connection with actuating the analyte sensor system 308. For example, the actuation detection component 545 may include an air pressure sensor that may be configured to detect changes in air pressure. The air pressure sensor may be stored with the analyte sensor system 308 in packaging that is pressurized above (e.g., greater than 1 atmosphere) or below (e.g., vacuum) standard normal air pressure conditions. An act of breaching (e.g., opening, puncturing, etc.) the packaging associated with the analyte sensor system 308 may then result in a change in pressure. The pressure transient event may then be used as a detectable event to trigger actuation of the analyte sensor system 308 when the packaging is breached and the pressure changes. The analyte sensor system 308 may be configured to have a flexible portion (e.g., a diaphragm) that may enable a pressure change outside of a moisture-proof volume (e.g., a sensor measurement electronics housing) within the analyte sensor system 308 to be detected within the moisture-proof volume. When the analyte sensor systems 308 are delivered in a multi-pack configuration, each analyte sensor system 308 in the multi-pack may have an individual pressurized chamber within the packaging such that each analyte sensor system 308 may individually exit a lower power state based on pressure changes.

[0218] In an embodiment, the actuation detection component 545 includes a microphone (e.g., a passive or active device) that is located within the analyte sensor system 308 and can be used to detect an audio signal or signature indicative of deployment of the analyte sensor system 308. For example, the audio signal / signature can be associated with the applicator deploying the analyte sensor system 308 (e.g., applicator trigger, mechanism, impact with a user). Such an audio signal / signature can be unique to a deployment event, such that the audio signal / signature can be used to trigger the analyte sensor system 308 to exit a lower power state.

[0219] In some embodiments, the actuation or waking of the analyte sensor system 308 may be triggered based at least in part on successful deployment of the analyte sensor system 308, determined at least in part on detection of a sound or acoustic signature indicative of successful deployment by a display device configured to provide information about the analyte sensor system 308 to a user. Such embodiments may provide for premature deployment failure detection and / or successful deployment detection. For example, certain spring-loaded applicators may emit sounds or have acoustic signatures during the deployment operation from which timing of moving parts may be inferred without opening or inspecting the applicator. Thus, for example, an application running on any of the display devices 110, 120, 130, 140 may be configured, when opened and executed, to distinguish failed deployments of the analyte sensor system 308 from successful deployments, and in some cases, further infer the specific cause of the failed deployment by analyzing sounds made by the applicator during deployment. Such an embodiment would not only allow for an alternative, and in some cases complementary, method of verifying successful deployment for proper wake-up of the analyte sensor system 308, but also allow for troubleshooting the cause of a particular deployment failure in the field in near real-time without the need to return a faulty applicator and / or analyte sensor system 308 to the manufacturer to investigate the cause of the failure. Such information can be valuable in that it at least allows for review of problems mapped to specific applicator lots, allows for further innovation in future applicator and analyte sensor system designs, and can reduce costs associated with returning and investigating faulty applicators.

[0220] In some embodiments, the microphones of the display devices 110, 120, 130, 140 may be configured to generate a recording of one or more audio waveforms and / or spectrograms of sounds made by the applicator and / or analyte sensor system 308 during deployment. An application running on the display devices 110, 120, 130, 140 may be configured to analyze the one or more recorded waveforms and / or spectrograms and, based on the analysis, distinguish successful deployments from unsuccessful deployments. For example, the application may be configured to record audio waveforms and / or spectrograms at a predetermined sampling rate (e.g., 96 kHz) such that a desired granularity in the time course of deployment can be obtained (e.g., the ability to distinguish aspects of sound and / or audio signatures of 1 ms ±0.025 ms). In some embodiments, the application may be configured to isolate, correlate, and / or identify portions of the recorded waveforms and / or spectrograms indicative of distinctive components of the applicator and / or analyte sensor system 308 performing known movements as part of the deployment process, and to identify whether and / or when such distinctive components are performing such known movements within a time frame at a particular speed and / or at an appropriate time with respect to one or more other movements or sounds associated with the deployment sufficient to infer a successful or failed deployment. Examples of such isolated sounds may include, but are not limited to, one or more clicks indicative of a component latching and / or releasing from another component, and / or one or more bangs or sound peaks indicative of a drive wheel or booster moving, rotating, and / or stopping. In some embodiments, upon determination of a failed deployment, the application may provide one or more notifications to the user indicative of a failed deployment, e.g., "remove sensor", or alternatively, one or more notifications to the user indicative of a successful deployment. In some embodiments, upon determining that the deployment was successful, the application may provide one or more notifications to the user indicative of a successful deployment.

[0221] The actuation detection component 545 may include an optical sensor that may be used to cause the analyte sensor system 308 to exit a lower power state. By way of example, such an optical sensor may be photovoltaic. A voltage may be generated based on exposure of the optical sensor to photons. The generated voltage may then be compared to a threshold value, and the result of the comparison may be used to trigger actuation of the analyte sensor system 308. Thus, an optical-based sensor may use light exposure for actuation purposes. The sensor may be external to the analyte sensor system 308, or may be located within the analyte sensor system 308 and covered by an optically transparent portion of the housing of the analyte sensor system 308, for example, such that light may still reach the optical sensor. In an embodiment, the optical sensor may include a CMOS device, a CCD device, a photodiode, a photoresistor, and / or a phototransistor that may be triggered by exposure to normal daylight conditions or when light exposure meets a threshold condition. Such optical sensors may be considered part of an actuation detection component 545 that is separate from the actuation detection circuit 520, or may be included within the actuation detection circuit 520. In one example, a user equipment (UE) device (e.g., display device 310) may provide a light signal that may be used to actuate the analyte sensor system 308 (e.g., an LED light source from the UE device may be used). In another example, the exposure may occur when a sticker or other element covering the detector is automatically removed when the analyte sensor system 308 is removed from an applicator or packing of the analyte sensor system 308.

[0222] The actuation detection circuit 520 and / or actuation detection component 545 may include a conductivity-based sensor that may be used to trigger the analyte sensor system 308 to exit a lower power state. Such a sensor may utilize a resistance measured through the user's skin when the analyte sensor system 308 is deployed. For example, the conductivity-based sensor may measure a large (e.g., open circuit) resistance before the analyte sensor system 308 is deployed and the analyte sensor 10 is implanted in the user. However, once the analyte sensor system 308 is deployed and the analyte sensor 10 is implanted, the resistance measured by the conductivity-based sensor may decrease through a conductive path through the user's skin. The conductive path may be measured between two electrodes of the actuation detection circuit 520 and / or actuation detection component 545. For example, a first conductive probe may contact the surface of the user's skin during deployment, and a resistance from the first conductive probe to the electrodes of the analyte sensor 10 is measured, with the measured resistance during deployment detectably lower than before deployment. Alternatively or additionally, two or more conductive probes may contact the surface of the user's skin at different locations separated by a distance (e.g., a few millimeters), and a lower resistance may be measured between these (e.g., two) conductive probes after deployment of the analyte sensor system 308 relative to the resistance measured between the probes before deployment. The change in measured resistance before and after deployment may be used to trigger the analyte sensor system 308 to exit a lower power state.

[0223] In some cases, one or more electromechanical or mechanical switches or sensors may be used for actuation purposes. In an embodiment, the actuation detection component 545 includes a switch-based sensor. For example, a mechanical switch may be located on the analyte sensor system 308. The switch may be sealed (e.g., using a gasket) such that the outer and inner portions of the analyte sensor system 308 may be isolated from one another. The switch-based sensor may use a momentary or latching switch and may be used to connect the circuitry of the analyte sensor system 308 to a power source (e.g., a battery of the analyte sensor system 308) to trigger a circuit wake-up (e.g., by making a connection via a wake-up pin). The switch may be triggered by unpacking / unpacking the analyte sensor system 308 with the applicator during deployment and / or by the analyte sensor system 308 bumping / impacting the user during deployment. The switch may be mechanically triggered and released once the analyte sensor system 308 is deployed.

[0224] In an embodiment, the actuation detection circuit 520 and / or actuation detection component 545 may include two or more exposed contacts configured with an open circuit that may be used to cause the analyte sensor system 308 to exit a lower power state. As an example, an electrical contact external to the analyte sensor system 308 may be part of an open circuit internal to the analyte sensor system 308. Actuation of the analyte sensor system 308 may be triggered by bridging two such electrical contacts (e.g., using an electrical jumper) such that the electrical contacts form an electrical connection with each other (e.g., forming a bridge using another conductive material). Alternatively, two such electrical contacts may already be electrically connected with each other and the act of breaking this connection may trigger actuation of the analyte sensor system 308. For example, bridging or unbridging / breaking electrical contacts may pull a node up or down to trigger actuation of the analyte sensor system 308 and / or form a connection to a battery of the analyte sensor system 308 as a means to trigger actuation. Aspects of this are further described with reference to FIG. 6C.

[0225] The bridges described above may be located in or may be part of the applicator of the analyte sensor system 308 such that the bridges may be used to trigger actuation (e.g., the bridges may be broken or formed) when the analyte sensor system 308 exits the applicator. The bridges may be located on a base plate of the analyte sensor system 308 and may be used to trigger actuation (e.g., the bridges may be broken or formed) during assembly of the analyte sensor system 308. For example, during assembly of a pre-connected analyte sensor system 308, two mechanically separated / connectable pieces may be joined by a user or applicator, which may form or break a bridge and trigger actuation.

[0226] The bridges mentioned above may be used to connect power (e.g., from the battery of the analyte sensor system 308) or to trigger circuit wake-up (e.g., using a wake-up pin). The bridges may be used to facilitate automatic wake-up of a pre-connected analyte sensor system 308 via needle retraction, where the needle acts as a bridge (such as a jumper) between two sets of contacts on a circuit board using a multi-layer gasket with an insulating layer in the middle that separates the two conductive layers. While the needle bridges the gasket, the circuit may be bridged / closed. And when the needle retracts (e.g., during deployment of the analyte sensor system 308), the circuit may be broken / opened / unbridged and trigger an actuation. One benefit of using a gasket through the needle path is the reduction in the size of the opening through the analyte sensor system 308 assembly, which may help with potential concerns regarding ingress of debris and visibility of blood to the user. This may help prevent debris and excess moisture from reaching the wound site and hide the blood from the user.

[0227] 6A illustrates an applicator 7100 for an on-skin sensor assembly of an analyte sensor system 308, according to an embodiment of the present disclosure. The applicator 7100 may include an actuating element 7104 disposed on a side of the applicator 7100, for example, on a side of an outer housing 7101 of the applicator 7100. In some embodiments, the actuating element 7104 may be a button, a switch, a toggle, a slide, a trigger, a knob, a rotating member, a portion of the applicator 7100 that deforms and / or bends, or any other suitable mechanism for actuating the insertion of the analyte sensor 530 and / or the retraction assembly of the applicator 7100. In some embodiments, the actuating element 7104 may be disposed in any location, for example, on the top, upper side, lower side, or any other location of the applicator 7100. The applicator 7100 may be large enough for a host to grasp in their hand and press or otherwise actuate the actuating element 7104, for example, with their thumb, or with their index and / or middle fingers. The applicator 7100 may be appropriately sized to accommodate the analyte sensor system 308 as well as one or more components of the actuation detection component 545 described above.

[0228] The applicator 7100 may be configured with one or more safety features that may prevent the applicator 7100 from being actuated until the safety feature is deactivated. In one embodiment, the one or more safety features may prevent the applicator 7100 from being actuated unless the applicator 7100 is pressed against the host's skin with sufficient force. Additionally, the applicator 7100 may be further configured such that one or more components retract internally based at least in part on one or more components pressing against the host's skin with a force exceeding a predetermined threshold, rather than based on one or more components translating beyond a predetermined static distal position. In other words, the applicator 7100 may implement a force-based retraction trigger, rather than being limited to a displacement-based retraction trigger.

[0229] Figure 6B shows an exploded perspective view of the applicator 7100 of Figure 6A, according to some embodiments. As shown, the applicator 7100 can include an outer applicator housing 7101, which can include an actuating element 7104. The outer applicator housing 7101 can be configured to translate distally upon force applied by the host to the applicator 7100, and in particular the inner housing 7102, thereby aligning the actuating element 7104 with a position from which the applicator 7100 can be fired.

[0230] The applicator 7100 may further include an inner housing 7102 configured to house at least one or more mechanisms utilized to apply the analyte sensor assembly 360 to the skin of a host (e.g., as referenced above in connection with FIG. 3A). As noted above, the analyte sensor assembly 360 may include or house the analyte sensor system 308. A distal surface 7130 of the bottom opening of the inner housing 7102 may define a bottom surface of the applicator 7100. In some embodiments, when the applicator 7100 is pressed against the skin of the host, the skin may deform into a substantially convex shape at the distal surface 7130. At least a portion of a surface of the skin disposed at the bottom opening of the applicator housing 7102 extends proximally beyond a plane defined by the distal surface 7130 into the bottom opening of the inner housing 7102. One or more components of the actuation detection component 545 described above may be included in or on the inner housing 7102, such as, for example, an NFC component, a magnet, or the like, or any other of the components described above that may be external to the analyte sensor system 308. In some embodiments, a barrier layer 7194 of may be disposed over a bottom opening of the inner housing 7102.

[0231] Actuation of the applicator 7100 may include the host pressing the applicator 7100 against the skin with sufficient force to translate the outer housing 7101 in a distal direction relative to the inner housing 7102 until the actuating element 7104 aligns with the opening 7106 in the inner housing 7102. Once such alignment is achieved, the host may initiate (e.g., push) the actuating element 7104. In some other embodiments, the applicator 7100 may be configured such that the actuating element 7104 may be actuated first, but the actual insertion is not triggered until the outer housing 7101 has translated sufficiently distally relative to the inner housing 7102. In still other embodiments, the actuating element 7104 may be biased toward the center of the applicator 7100 such that the actuating element 7104 does not need to be explicitly actuated by the host, but instead the actuating element 7104 may be configured to automatically initiate insertion once the outer housing 7101 has translated sufficiently distally relative to the inner housing 7102.

[0232] As an example, FIG. 6C illustrates a bridge-based sensor or switch that may be used in connection with the operation of the analyte sensor system 308. FIG. 6C illustrates a portion of an analyte sensor electronics module 600 that is connectable to an analyte sensor 602 using a first contact 604 and a second contact 606. For example, the analyte sensor electronics module 600 may be connected to the analyte sensor 602 before the analyte sensor 602 is implanted in a user. The analyte sensor electronics module 600 may include a conductive bridge 612 (e.g., a jumper) that may be configured to electrically couple the first contact 604 and the second contact 606 to one another to form a bridge during deployment / application of the analyte sensor system 308. The conductive jumper 612 may be located at least partially between two electrical connections of the analyte sensor system 308. The conductive jumper 612 can include two springs 608 coupled by a conductive link 616, where the conductive jumper 612 and springs 608 are supported by a housing 614 of the analyte sensor system 308. During deployment / application of the analyte sensor system 308, the springs 608 can deflect such that the springs 608 electrically connect to each other via physical contact, thus forming a bridge that can be used to trigger actuation of the analyte sensor system 308.

[0233] Referring again to FIG. 5 and, by way of example, to FIG. 6C, the actuation detection circuit 520 and / or actuation detection component 545 may, in various embodiments, include a non-conductive breakaway tab-type sensor or switch that may be used to cause the analyte sensor system 308 to exit a lower power state. For example, a non-conductive material may be placed between spring-loaded electrical contacts. Removal of the non-conductive material may then cause the spring-loaded electrical contacts to form a physical / electrical connection such that the contacts are electrically coupled. These spring-loaded electrical contact connections may be used to connect a power source (e.g., from a battery in the analyte sensor system 308) and / or trigger a circuit wake-up (e.g., as a wake-up pin) to cause the analyte sensor system 308 to exit a lower power state.

[0234] In an embodiment, the actuation detection circuit 520 and / or the actuation detection component 545 may include a strain / force-based sensor that may be used to cause the analyte sensor system 308 to exit a lower power mode. One or more sensors may be included in the analyte sensor system 308 that may be capable of detecting a strain (e.g., total deformation divided by the initial dimensions of the body) or force disposed on the housing / body of the analyte sensor system 308. Such a strain or force may be applied, for example, by an applicator gripping the analyte sensor system 308. In some examples, a strain gauge may be used inside the housing of the analyte sensor system 308, where the strain gauge may be electrically coupled to the actuation detection circuit 520, for example, via routing on a printed circuit board. The strain gauge may be disposed on or coupled to a Wheatstone bridge. The strain gauge may vary a resistance value that may be monitored using a Wheatstone bridge. Various types of strain gauge configurations may be used in conjunction with a Wheatstone bridge, for example, a quarter bridge, half bridge, full bridge, depending on the orientation of the strain gauges and the type of strain to be measured. Strain / force measurements may also be used to detect momentary effects such as acceleration forces during deployment of the analyte sensor system 308 and / or impact of the analyte sensor system 308 on the user's body. For example, strain / force measurements may be used to effect triggers 906 and / or 910, with reference to FIG. 9.

[0235] In certain embodiments, the actuation detection circuit 520 and / or actuation detection component 545 may include additional components that may be added internally or externally to the analyte sensor system 308, particularly to create detectable events that may be used to trigger actuation of the analyte sensor system 308 without user intervention. In one example, a current generation component may be used in conjunction with the analyte sensor system 308 for actuation purposes. For example, magnetizing or adding a magnetic element to the applicator needle or needle hub may be used for actuation purposes. When the analyte sensor system 308 is deployed, a magnetic needle or auxiliary magnetic rod may be retracted relative to the analyte sensor system 308. The actuation detection component 545 may include an inductive coil or NFC antenna that may be used to generate a current (e.g., or other electrical signal) via an electromagnetic response, for example, around the analyte sensor system 308. The movement of the applicator withdrawing the needle, rod, or other magnetic element may create relative motion between it and the coil / antenna of the analyte sensor system 308. This current or other electrical signal can then be used to trigger actuation of the analyte sensor system 308. In some cases, the analyte sensor system 308 may already include an NFC antenna, and thus this functionality may not require the addition of components to the analyte sensor system 308.

[0236] In another example, a piezoelectric component may be used that generates a voltage in response to forces (e.g., impact forces) that may occur during deployment of the analyte sensor system 308. For example, the actuation detection circuit 520 and / or the actuation detection component 545 may include a quartz crystal, such that when the analyte sensor system 308 experiences a deployment-based impact, the voltage generated by the crystal spikes or increases, triggering the analyte sensor system 308 to exit a lower power state.

[0237] Exiting a lower power state in response to user-based input In certain embodiments, a switch / sensor / mechanism / approach can be used to detect a user step and use it to trigger activation of the analyte sensor system 308, either alone or in combination with other activation detection approaches / means described herein. Such a switch / sensor / mechanism / approach can typically rely on user intervention / action. In some examples, a detection switch / element / sensor can be disposed on the analyte sensor system 308 and used to trigger activation or exit a lower power state. As an example, at least a portion of the activation detection component 545 can include a detection element / component that is external to the analyte sensor system 308, such as a removable sticker on the surface of the analyte sensor system 308. In response to a user peeling / removing the sticker, the analyte sensor system 308 can be triggered to exit a lower power state. As another example, the detection element can be a feature of an applicator, packaging, box, or tray associated with the delivery of the analyte sensor system 308. Now, referring to, for example, FIG. 6A and FIG. 6B. In some cases, the sensing element may be a component located in the packaging near the analyte sensor system 308 .

[0238] The sensing element may include a conductive material (e.g., metal, graphite, etc.), and in embodiments, a sensor (e.g., using capacitive, inductive magnetic, RF, or other types of sensing as described herein) may detect removal of the conductive material when the sensing element is removed by a user. In certain embodiments, the sensing element may include a tag device (e.g., RFID sticker, etc.) that may be placed on a surface of the analyte sensor system 308 during its manufacture / assembly. A reader (e.g., NFC, RFID, etc.) may then detect the removal of the tag and trigger an actuation. For example, ping messages may be exchanged when the tag device is in place, and when the tag device is removed, the exchange no longer occurs and an actuation may be triggered.

[0239] In some cases, the detection element may be optically opaque such that removal of the detection element exposes the light sensor and may trigger actuation. For example, the light sensor may be exposed by peeling back a sticker to expose the light sensor. Alternatively, the detection element may be optically colored (e.g., green or another color). Such removal of the detection element may thus result in a shift in wavelength that may be detected using the light sensor. As an example, the color shift may change from green to white, etc., and the color change may be used to trigger actuation.

[0240] Certain of the above-mentioned electromechanical detection techniques may be used in conjunction with an embodiment that utilizes a user step to activate the objective or analyte sensor system 308. For example, a user may trigger activation of the analyte sensor system 308 by pressing a button, pulling a tab, performing a step that forms or breaks a bridge, etc. The user may be instructed to perform such steps before or after implantation of the analyte sensor 10, or within a particular time frame thereof.

[0241] In an embodiment, a signal from an external device or a signal generated based on user input may be used to trigger actuation of the analyte sensor system 308. As an example, a display of an electronic device (e.g., a smartphone, a proprietary analyte display device, or a smartwatch, see FIG. 1 ) may be used to direct light (e.g., from the device's flash or screen, as described above), sound (e.g., frequency), or vibration to the analyte sensor system 308. The actuation detection circuit 520 and / or actuation detection component 545 may then be used to detect such external stimuli, e.g., via a photodiode, microphone, or piezoelectric sensor, and trigger actuation in response thereto. In one example, a user may tap a pattern on the analyte sensor 308 that may be detected using a microphone and / or accelerometer and used to trigger actuation. The accelerometer of the analyte sensor system 308 may also be used for actuation purposes, e.g., human gait / walk pattern detection. That is, if the analyte sensor system 308 detects that a human is moving according to a human gait, it may infer that implantation of the analyte sensor 530 has occurred.

[0242] It should be understood that each of the above-mentioned techniques may be used alone or in combination with any of the other above-mentioned techniques for causing the analyte sensor system 308 to exit a lower power state. The technique or techniques used may depend on system design considerations, including, for example, considerations regarding power consumption, weight, size, and level of user interactivity, among others.

[0243] Using a State Machine to Exit a Lower Power State One or more embodiments disclosed herein may utilize impedance measurements and / or current counts indicative of current flow through an analyte sensor (e.g., analyte sensor 530 of FIG. 5) to determine when the analyte sensor is deployed within the skin of a host and, therefore, when at least a portion of the sensor electronics (e.g., by way of example and not limitation, analyte sensor system 308 of FIG. 5) should exit a lower power “storage” or “sleep” mode and “wake up” to begin processing one or more samples of sensor signals and / or sensor data. Additionally or alternatively, such current counts and / or impedance measurements may be utilized when the sensor electronics of such analyte sensor system 308 transitions to a powered “run” mode to periodically or randomly calibrate or recalibrate the analyte sensor 530 and / or monitor the sensitivity of the analyte sensor 530.

[0244] Some embodiments may utilize a clocked processor-based controller (e.g., processor / microcontroller 535 of FIG. 5) to provide one or more pulsed voltages across the terminals of the analyte sensor 530, perform continuous current counts and / or impedance measurements or determinations of the analyte sensor 530 based on the response to the pulsed voltages, and average and analyze the current counts and / or impedance measurements. Such pulsed voltages may have durations on the order of milliseconds, and an accurate estimation of the average current through the analyte sensor 530 and / or the impedance of the analyte sensor 530 may require many current count samples (e.g., 125) averaged over an extended period of time (e.g., 10-12 seconds). While such a controller-based solution is shown to work, constantly powering the clocked processor-based controller 535 during the sample acquisition process would require a significant amount of power and may cause an on-board battery to last less than the rated capacity of the on-board battery.

[0245] One solution, as described in more detail below in connection with at least FIGS. 12-15, is to offload such controller-based methods for measuring and / or determining a current count indicative of current through the analyte sensor 530 to a hardware-based state machine (e.g., state machine 1430 of FIG. 14), which consumes significantly less power than the clock-processor-based controller 535. In such a solution, the clock-processor-based controller 535 sets one or more parameters of the state machine 1430 and then transitions to a lower power "sleep" state rather than the controller 535 itself performing all the actions by staying "awake" and undesirably draining the battery. In some embodiments, the state machine 1430 may be implemented utilizing one or more registers (e.g., parameter register 1436 of FIG. 14), one or more counters (e.g., counter 1434 of FIG. 14), and / or one or more memories (e.g., a portion of storage device 515 of FIG. 5).

[0246] While the controller 535 is in a lower power "sleep" state, the state machine 1430 may perform the tasks of controlling the application of one or more pulsed voltages across the terminals of the analyte sensor 530, controlling the measurement of a current induced in the analyte sensor 530 by the one or more pulsed voltages, and storing one or more data samples (e.g., digital counts) based on the current response. The controller 535 may then wake up in response to an interrupt or wake signal from the state machine 1430 to process one or more stored data samples, the number of which may be variable based on the particular implementation. Such a solution may reduce the overall power consumption of the analyte sensor system 308 by 50-60% or more in some cases, as compared to the data acquisition process described above that utilizes only a clocked processor-based controller 535.

[0247] The state machine 1430 can be utilized to capture, at least partially process, and / or store current counts corresponding to the current flowing through the analyte sensor during an “archive” mode, when the controller is generally “asleep”, or during a “run” mode, when successive analyte (e.g., glucose) measurements are being measured, determined, estimated, and / or otherwise processed.

[0248] During such a "storage" mode, the analog front end (AFE) of the analyte sensor system (e.g., at least a portion of the sensor measurement circuitry 525 of FIG. 5) may wake periodically (e.g., every 64 seconds) to perform one or more current count measurements indicative of the current through the analyte sensor 530 to determine whether the analyte sensor 530 is inserted into the host's skin, which would indicate a transition from the "storage" mode to the "run" mode or "wake" state is appropriate. This process may also be utilized to distinguish current count values ​​indicative of the analyte sensor 530 being properly inserted into the skin from current count values ​​indicative of the analyte sensor 530 being exposed to environmental conditions (e.g., high relative humidity) that may erroneously indicate sensor insertion into the host's skin. Thus, this process may help to avoid false wake-ups of the controller 535 due to, for example, high relative humidity conditions, as described in more detail below. For example, when the analyte sensor 530 is inserted into the host's skin, a relatively moderate to lower impedance (e.g., hundreds of kΩ) of the analyte sensor 530 will result in a particular observed current flow through the analyte sensor 530. However, when the relative humidity is sufficiently high (e.g., >90%) but the analyte sensor 530 is not inserted into the host's skin, a relatively high but not open circuit impedance (e.g., 1.6 MΩ) of the analyte sensor 530 will result in a different observed current flow through the analyte sensor 530, with the higher the relative humidity, the greater the observed current flow through the analyte sensor 530 (see, e.g., FIG. 7C). The state machine 1430 described herein allows for the distinction between these two states to ensure that these environmental conditions (e.g., sufficiently high relative humidity) do not erroneously trigger a false wake-up of the controller 535, thereby further reducing power consumption due to unnecessary and inappropriate wake-up of the controller 535.

[0249] 12 illustrates a state diagram 1200, for example associated with the state machine 1430 of FIG. 14, for determining one or more current counts indicative of at least the current through the analyte sensor 530, according to some embodiments. The state diagram 1200 illustrates seven potential states: five potential delay states (e.g., DELAY 1 WE_L state 1206, DELAY 2 WE_L state 1212, DELAY 1 WE_H state 1216, DELAY 2 WE_H state 1224, and IDLE state 1228) and two potential sampling states (e.g., PRE-COUNT SAMPLING state 1208 and PULSE COUNT SAMPLING state 1220). The operation of the state machine 1430 is described in more detail below in connection with FIGS. 13-15, but a brief overview here may be helpful in understanding the functionality and usefulness of the different states.

[0250] To ultimately determine the impedance of the analyte sensor 530, a known voltage may be applied across the terminals of the analyte sensor 530, and Ohm's law may be used to determine the impedance based on the current generated by the known voltage. However, the current generated by the known voltage may have components that are not necessarily directly attributable to the membrane impedance of the analyte sensor 530, for example, but are attributable to other environmental factors. Thus, an impedance determined based on a single current or current count measured in response to application of a known voltage across the sensor terminals may not accurately reflect the actual membrane impedance of the analyte sensor 530, and therefore may not be a reliable indicator for changing the state of the analyte sensor system 308, for example, from a "sleep" or "store" state to a "wake" or "run" state. Thus, it may be desirable to utilize multiple current or current count measurements to make such state change determinations.

[0251] Thus, a first current count value may be determined while the working electrode of the analyte sensor 530 is held at a first potential. This first current count may be considered a baseline value. The working electrode of the analyte sensor 530 may then be held at a second potential, higher than the first potential, and a second current count value may be determined. This second current count value may be considered a pulse value. If the interval between measurements of the first and second current count values ​​is small enough, subtracting the first current count value from the second current count value can reliably remove much of the effect of environmental factors from the measurement, and with such a small enough interval between measurements, the effect of such environmental factors can be assumed to be similar to the effect on both the first and second current counts, from which an accurate membrane impedance value of the analyte sensor 530 can be obtained, based on the understanding that such impedance is inversely proportional to the difference between the first and second current counts.

[0252] However, when the first and second potentials are applied across the terminals of the analyte sensor 530, the initial instantaneous current induced through the analyte sensor 530 does not represent the steady-state impedance of the sensor as determined according to Ohm's Law due to the RC characteristics of the analyte sensor 530, e.g., as described above in connection with Figure 7A. Thus, by implementing one or more delay states 1206, 1212, 1216, 1224, it may be ensured that the measured current count during the sampling states 1208, 1220 is not substantially affected by the initial dynamics of the RC characteristics of the analyte sensor 530.

[0253] As shown in FIG. 12, the order of states 1206, 1208, 1212, 1216, 1220, 1224, and 1228 is always the same, but all states except for pre-count sampling state 1208 can be bypassed by controller 535 according to pre-configuration of state machine 1430 (see FIG. 14) and / or associated parameter register 1436 (see FIG. 14). Each state in FIG. 12 can also have a pre-configured duration. A counter (e.g., counter 1434 in FIG. 14) can continuously count during each valid state until a configurable absolute value is reached, triggering a change to the next valid state and a reset of counter 1434 to time the next valid state. In some embodiments, this process allows a single counter 1430 to time all valid states of state machine 1430, thereby simplifying the analyte sensor system design and reducing associated manufacturing costs.

[0254] The state diagram 1200 begins at a start block 1202 and proceeds to block 1204 to determine whether a first delay state 1206 (e.g., DELAY1WE_L) is enabled. If the first delay state 1206 is disabled, the state diagram 1200 proceeds from block 1204 directly to a first sampling state 1208. If the first delay state 1206 is enabled, the state diagram 1200 proceeds to a first delay state 1206, which can last for a configurable duration, for example, about 1-2 milliseconds or any other suitable duration. At the start of the first delay state 1206, the state machine 1430 can apply or control the application of a first potential to a working electrode of the analyte sensor 530. During the first delay state 1206, there are no current count measurements captured by the state machine 1430 and / or by supporting hardware or software, at least as illustrated in FIG.

[0255] Upon expiration of the first delay state 1206, the state diagram 1200 proceeds to a first sampling state 1208, during which a first voltage is maintained at the working electrode of the analyte sensor 530 and one or more samples (e.g., digital counts) corresponding to a current induced in the analyte sensor 530 by the first potential are captured and / or processed by the state machine 1430 and / or supporting hardware or software, at least as illustrated in Figure 14. The first sampling state 1208 can last for a configurable period of time, for example, between about 2 seconds and 300 seconds, depending on the application.

[0256] When the first sampling state 1208 expires, the state diagram 1200 proceeds to block 1210 to determine whether a second delay state 1212 (e.g., DELAY2 WE_L) is enabled. If the second delay state 1212 is disabled, the state diagram 1200 proceeds from block 1210 directly to block 1214. If the second delay state 1212 is enabled, the state diagram 1200 proceeds to the second delay state 1212, which can last for a configurable duration, for example, about 1-2 milliseconds or any other suitable period of time. The state machine 1430 can maintain or control the maintenance of the first potential at the working electrode of the analyte sensor 530 for the duration of the second delay state 1212. During the second delay state 1212, there are no current count measurements captured by the state machine 1430 and / or by supporting hardware or software, at least as illustrated in FIG.

[0257] Upon expiration of the second sampling state 1212, the state diagram 1200 proceeds to block 1214 to determine whether a third delay state 1216 (e.g., DELAY1WE_H) is enabled. If the third delay state 1216 is disabled, the state diagram 1200 proceeds from block 1214 directly to block 1218. If the third delay state 1216 is enabled, the state diagram 1200 proceeds to the third delay state 1216, which can last for a configurable duration, for example, about 1-2 milliseconds, or any other suitable duration. At the start of the third delay state 1216, the state machine 1430 can apply or control the application of a second potential, which is higher than the first potential, to the working electrode of the analyte sensor 530. An initial current flow through the analyte sensor 530 due to the RC characteristics of the analyte sensor 530 may occur and decay substantially during the third delay state 1216. Thus, during the third delay state 1216, there are no current count measurements captured by the state machine 1430 and / or by supporting hardware or software, at least as illustrated in FIG.

[0258] Upon expiration of the third delay state 1216, the state diagram 1200 proceeds to block 1218 to determine whether the second sampling state 1220 is enabled. If the second sampling state 1220 is disabled, the state diagram 1200 proceeds from block 1218 directly to block 1222. If the second sampling state 1220 is enabled, the state diagram 1200 proceeds to the second sampling state 1220 during which a second voltage is maintained at the working electrode of the analyte sensor 530 and one or more samples (e.g., digital counts) corresponding to a current induced in the analyte sensor 530 by the second potential are captured and / or processed by the state machine 1430 as described in more detail below in connection with FIGS. 13-15. The second sampling state 1220 can last for a configurable period of time, for example, about 3-4 seconds, depending on the application.

[0259] Upon expiration of the second sampling state 1220, the state diagram 1200 proceeds to block 1222 to determine whether a fourth delay state 1224 (e.g., DELAY2WE_H) is enabled. If the fourth delay state 1224 is disabled, the state diagram 1200 proceeds from block 1222 directly to block 1226. If the fourth delay state 1224 is enabled, the state diagram 1200 proceeds to the fourth delay state 1224, which can last for a configurable duration, for example, about 1-2 milliseconds or any other suitable duration. The state machine 1430 can maintain or control the maintenance of the second potential at the working electrode of the analyte sensor 530 for the duration of the fourth delay state 1224. During the fourth delay state 1224, there are no current count measurements captured by the state machine 1430 and / or by supporting hardware or software, at least as illustrated in FIG.

[0260] Once the fourth delay state 1224 has expired, the state diagram 1200 proceeds to block 1226 to determine whether a fifth delay state 1228 (e.g., an extended idle state) is enabled. If the fifth delay state 1226 is disabled, the state diagram 1200 returns directly from block 1226 to block 1204, and the state machine 1430 again executes the entire state diagram 1200. If the fifth delay state 1228 is enabled, the state diagram 1200 proceeds to the fifth delay state 1228, which can last for a configurable duration, for example, from about 1 millisecond to 64 seconds, or any other suitable duration. At the start of the fifth delay state 1228, the state machine 1430 can reapply or control the reapplication of the first potential to the working electrode of the analyte sensor 530, can provide or control the provision of 0 V to the working electrode of the analyte sensor 530, or can provide or control the provision of an open circuit voltage (e.g., a high Z state) to the working electrode of the analyte sensor 530 (e.g., by opening a switch in a circuit including the analyte sensor 530). This potential can be maintained at the working electrode for the duration of the fifth delay state 1228. During the fifth delay state 1228, there are no current count measurements captured by the state machine 1430 and / or by supporting hardware or software, at least as illustrated in FIG. 14 .

[0261] In some embodiments, activation of the fifth delay state 1228 can be reserved for operation of the state machine 1430 during a storage mode in which the analyte sensor 530 is not actively measuring analyte values, during which samples may be collected only intermittently during the first sampling state 1208 and / or the second sampling state 1220 occurring during longer periods of inactivity, primarily defined by the duration of the fifth delay state 1228.

[0262] Further, the first and second voltages described above may be fully configurable and, in some cases, independently configurable from one another. For example, the first and second voltages may be programmable from 0V to 1V in approximately 16mV steps (e.g., 64 steps). In addition, the first and second voltages may each have different values ​​depending on whether the analyte sensor system 308 is currently in a "storage" mode during which the analyte sensor 530 is not inserted into the host's skin, or in a "run" mode during which the analyte sensor 530 is inserted into the host's skin and continuous and / or intermittent glucose measurements are taken, determined, and / or otherwise captured. For example, in such a "run" mode, the first voltage may be 0.6V and the second voltage may be 0.616V (e.g., 16mV greater than the first voltage), while in such a "store" mode, the first voltage may be 0V and the second voltage may be 0.016V (e.g., 16mV greater than the first voltage).

[0263] In some embodiments, the utilization of 0V for the first voltage during the “storage” mode may be advantageous because application of a defined non-zero bias voltage across the terminals of the analyte sensor 530 for extended periods of time may cause accelerated oxidation and / or damage to the sensor 530. For similar reasons, application of an open circuit voltage (e.g., a high Z state) or even 0V to the working electrode of the analyte sensor 530 during the fifth delay state 1228 helps to ensure that no potentially damaging bias voltage is applied across the terminals of the analyte sensor 530 for the often extended duration of the fifth delay state 1228, thereby reducing oxidation or other damage to the analyte sensor 530 during the “storage” mode before the analyte sensor 530 is deployed within the skin of the host.

[0264] Additionally, while example durations of each of the states of state diagram 1200 are provided above, the disclosure is not so limited and any suitable durations are contemplated. In some embodiments, counter 1434 of FIG. 14 may include a configurable bit counter. For example, counter 1434 may be configured as a 10-bit counter having a maximum value of 1 second and configurable in increments of approximately 976 microseconds (e.g., 1 / 1024 of a second) when timing each of first delay state 1206, second delay state 1212, third delay state 1216, second sampling state 1220, and fourth delay state 1224. In some embodiments, counter 1434 may be configured as a 19-bit counter having a maximum value of 8.53 minutes and configurable in increments of approximately 976 microseconds (e.g., 1 / 1024 of a second) when timing each of first sample state 1208 and delay state 1228.

[0265] The operation of the analyte sensor system 308, according to some embodiments, is further discussed below in conjunction with the timing diagram 1300 of FIG. 13 and the functional block diagram 1400 of FIG.

[0266] Timing diagram 1300 of FIG. 13 illustrates example timing of some signals associated with one or more of the states discussed above in connection with state diagram 1200 of FIG.

[0267] The Pulse_Count_Ready signal 1310 can be used to signal that a current count corresponding to the current flowing through the analyte sensor 530, as determined and integrated by an analog-to-digital converter (ADC) (e.g., sensor measurement circuit 525) of the analog front end (AFE) during the second sampling state 1220, is ready for transmission to one or more modules of FIG. 14.

[0268] The Pre_Count_Ready signal 1320 can be used to signal that the current count corresponding to the current through the analyte sensor 530, determined and integrated by the ADC of the AFE during the first sampling state 1208, is ready for transmission to one or more modules of FIG. 14.

[0269] The INT_Enable signal 1330 can be utilized to signal the ADC of the AFE to integrate current counts corresponding to the current through the analyte sensor 530 during one or both of the first sampling state 1208 and the second sampling state 1220 based on the signal 1330 being high at 1332 and 1334. The timing diagram 1300 also illustrates an exemplary working electrode potential 1340 of the analyte sensor 530 that is applied during one or more of the states 1206, 1208, 1212, 1216, 1220, 1224, 1228.

[0270] Block diagram 1400 of FIG. 14 illustrates example features of a state machine 1430 and at least some hardware and / or software features of the sensor measurement circuit 525, the actuation detection circuit 520, and / or the actuation detection component 545, e.g., as described above in connection with FIG. 5.

[0271] For example, block diagram 1400 illustrates a state machine 1430 that may include a parameter register 1436 configured to store one or more parameters of one or more states of state machine 1430, e.g., as described above in connection with FIG. 12. For example, parameter register 1436 may store an indication of whether each potential state of state diagram 1200 is valid and one or more configurable counter values ​​corresponding to the duration of each potential state of state diagram 1200. In some embodiments, one or more of the parameters of parameter register 1436 may be configured by controller 535 before controller 535 transitions to a sleep mode or lower power mode.

[0272] The state machine 1430 may further include a counter 1434 configured to count continuously during each valid state until a configurable counter value is reached. Such configurable counter value may be defined by a parameter register 1436. The counter 1434 reaching the configurable counter value may trigger a state change signal 1438 to advance the state machine 1430 to the next valid state. The counter 1434 may be configured to reset and begin counting the timing of the next valid state based on reaching the configurable counter value of a particular state. As shown, the counter 1434 may receive a clock signal 1432 that regulates such counting. In some embodiments, the clock signal 1432 may be derived from a clock signal of the AFE's ADC. For example, the ADC clock signal may be a 32 kHz clock signal provided, for example, by a highly accurate crystal. In some embodiments, this ADC clock signal may be divided by 32 to obtain a clock signal 1432 having a frequency of 1,024 Hz. However, the disclosure is not so limited and the clock signal 1432 may be obtained and / or generated in any suitable manner and may have any suitable frequency.

[0273] The block diagram 1400 further shows a pre-count sample buffer 1404 configured to receive and temporarily store one or more current count samples 1402 generated by the ADC based on the current flowing through the analyte sensor 530 during the pre-count sampling state 1208.

[0274] The block diagram 1400 further shows a differentiator 1406 configured to subtract the current count sample stored in the pre-count sample buffer 1404 from a subsequently received current count sample 1402 generated by the ADC based on the current through the analyte sensor 530 during the pulse count sampling state 1220. The differentiator 1406 can output the difference value to a multiplexer (MUX) 1412. Based on a difference mode enable signal 1410, the MUX 1412 can be configured to either pass the current count sample 1402 directly from the ADC (e.g., difference mode enable=0) or pass the calculated difference value from the differentiator 1406 (e.g., difference mode enable=1).

[0275] Block diagram 1400 further shows an accumulator 1414 configured to accumulate (e.g., integrate or sum) successive samples received from MUX 1412 and output the accumulated, integrated, or summed samples to MUX 1416. Based on a sum enable signal 1418, MUX 1416 can be configured to either pass the current count samples 1402 directly from MUX 1412 (e.g., sum enable=0) or pass the accumulated, integrated, or summed samples from accumulator 1414 (e.g., sum enable=1).

[0276] Block diagram 1400 further illustrates a sample buffer 1420 (e.g., a first-in, first-out FIFO buffer) configured to receive and store one or more samples from MUX 1416. In some embodiments, sample buffer 1420 is configured to store up to 16 samples simultaneously. However, the disclosure is not so limited and sample buffer 1420 may be configured to store any number of samples simultaneously, according to a particular implementation. In general, however, the more samples the sample buffer 1420 is configured to store simultaneously, the more power sample buffer 1420 will require.

[0277] The threshold detection module 1422 may be configured to determine whether a configurable number of consecutive or non-consecutive samples output from the MUX 1416 satisfy a predetermined and / or configurable threshold. The threshold detection module 1422 may be configured to generate a controller wake-up signal 1424 based on the satisfaction of a predetermined threshold by a configurable number of consecutive or non-consecutive samples. The controller 535 may be configured to wake up in response to the controller wake-up signal 1424, further process the samples stored in the sample buffer 1420, and / or transmit or control transmission of a signal based on such processing. In some embodiments, the controller 535 may be configured to re-enter a lower power sleep mode upon completion of such processing and / or signal transmission, while the process(es) described above are repeated.

[0278] Exemplary state-by-state operation will now be described in connection with Figures 13 and 14 when all delay states and all sampling states of state machine 1430 are valid, as discussed above in connection with Figure 12. For example, in some embodiments of the storage mode, state-by-state operation, difference mode enable signal 1410 and sum enable signal 1418 may both be set high such that MUX 1412 ends up passing the output of differentiator 1406, and MUX 1416 ends up passing the output of accumulator 1414.

[0279] 13, the state machine 1430 may initially transition to a first delay state 1206. During the first delay state 1206, a first potential 1340 (e.g., 0V in “store” mode, 0.6V in “run” mode) is applied to the working electrode of the analyte sensor 530. During the first delay state 1206, the INT_enable signal 1330 is low. Thus, the ADC of the sensor measurement circuit 525 is not integrating and / or accumulating current counts corresponding to the current through the analyte sensor 530 during the first delay state 1206. The counter 1434 receives a clock signal 1432 and continuously increments until it reaches a configurable absolute value defined by a parameter register 1436. Upon reaching the configurable absolute value, the counter 1434 and / or another portion of the state machine 1430 generates a state change signal 1438 , triggering a change to the pre-count sampling state 1208 and a reset of the counter 1434 .

[0280] A first potential 1340 (e.g., 0 V in “store” mode, 0.6 V in “run” mode) is maintained at the working electrode of the analyte sensor 530 for the duration of the pre-count sampling state 1208. The INT_Enable signal 1330 is set high, e.g., at 1332, for the duration of the pre-count sampling state 1208. Thus, the ADC of the sensor measurement circuit 525 integrates and / or accumulates current counts corresponding to the current through the analyte sensor 530 for the duration of the pre-count sampling state 1208.

[0281] During the pre-count sampling state 1208, the counter 1434 receives a clock signal 1432 and continuously increments until it reaches a configurable absolute value defined by a parameter register 1436 and corresponding to the duration of the pre-count sampling state 1208. Once the configurable absolute value is reached, the counter 1434 or another portion of the state machine 1430 generates a state change signal 1438 that causes the state machine 1430 to proceed to the second delay state 1212, set the INT_Enable signal 1330 low which signals the ADC to stop accumulating current count samples, and generate a pulse 1322 on the Pre_Count_Ready signal 1320 which signals the ADC to output the accumulated current count samples 1402 to the pre-count sample buffer 1404 and reset the counter 1434. This accumulated current count sample 1402 may represent the average current flowing through the analyte sensor 530 during the pre-count sampling state 1208. Although a single arrow signal line is shown, the accumulated current count sample 1402 may include multi-bit (e.g., 10-bit or 19-bit) sample values ​​transmitted in parallel from the ADC over a parallel (e.g., 10-bit or 19-bit) data bus to the pre-count sample buffer 1404. Unless otherwise noted, all samples passed by other signal paths in FIG. 14 may be similar multi-bit sample values ​​transmitted in parallel over similar parallel data buses shown with signal arrows in FIG.

[0282] Continuing with the discussion of FIG. 13, a first potential 1340 (e.g., 0V in “store” mode and 0.6V in “run” mode) is maintained at the working electrode of the analyte sensor 530 for the duration of the second delay state 1212. Because the INT_enable signal 1330 is low during the second delay state 1212, the ADC of the sensor measurement circuit 525 is not integrating and / or accumulating a current count corresponding to the current through the analyte sensor 530 during the second delay state 1212. The counter 1434 receives the clock signal 1432 and continuously increments until it reaches a configurable absolute value defined by a parameter register 1436. Once the configurable absolute value is reached, the counter 1434 or another portion of the state machine 1430 generates a state change signal 1438 that triggers a change to the third delay state 1216 and a reset of the counter 1434.

[0283] At the start of the third delay state 1216, a second potential 1342 (e.g., 16 mV in “store” mode, 0.616 V in “run” mode) is applied to the working electrode of the analyte sensor 530 and maintained for the duration of the third delay state 1216. During at least the rising edge 1344 of the second potential 1342, the current through the analyte sensor 530 is substantially dominated by the RC characteristics of the analyte sensor 530, such that the current substantially decays during the third delay state 1216. Because the INT_enable signal 1330 is low during the third delay state 1216, the ADC of the sensor measurement circuit 525 is not integrating and / or accumulating a current count corresponding to the current through the analyte sensor 530 during the third delay state 1216. The counter 1434 receives a clock signal 1432 and continuously increments until it reaches a configurable absolute value defined by a parameter register 1436. Once the configurable absolute value is reached, the counter 1434 or another portion of the state machine 1430 generates a state change signal 1438 that triggers a change to the pulse counting state 1220 and a reset of the counter 1434 .

[0284] A second potential 1342 (e.g., 16 mV in “store” mode, 0.616 V in “run” mode) is maintained at the working electrode of the analyte sensor 530 for the duration of the pulse count sampling state 1220. The INT_Enable signal 1330 is set high for the duration of the pulse count sampling state 1220. Thus, the ADC of the sensor measurement circuit 525 integrates and / or accumulates current counts corresponding to the current through the analyte sensor 530 for the duration of the pulse count sampling state 1220.

[0285] During the pulse count sampling state 1220, the counter 1434 receives a clock signal 1432 and continuously increments until it reaches a configurable absolute value defined by a parameter register 1436. Once the configurable absolute value is reached, the counter 1434 or another portion of the state machine 1430 generates a state change signal 1438 that causes the state machine 1430 to proceed to the fourth delay state 1224, set the INT_Enable signal 1330 low which signals the ADC to stop accumulating current count samples, and generate a pulse 1312 on the Pulse_Count_Ready signal 1310 which signals the ADC to output the accumulated current count sample 1402 to the differentiator 1406 and reset the counter 1434. This accumulated current count sample 1402 may represent the average current through the analyte sensor 530 during the pulse count sampling state 1220.

[0286] The differentiator 1406 is configured to subtract the accumulated current count sample 1402 stored at the end of the pre-count sampling state 1208 from the accumulated current count sample 1402 generated at the end of the pulse count sampling state 1220 and output the difference current count sample to a MUX 1412. The differentiator 1406 may be configured to set this difference current count sample to zero if this would otherwise result in a negative number. Because the differential mode enable signal 1410 is set high, the MUX 1412 passes the difference current count sample to an accumulator 1414 which stores the difference current count sample.

[0287] A second potential 1342 (e.g., 16 mV in the “store” mode and 0.616 V in the “run” mode) is maintained at the working electrode of the analyte sensor 530 for the duration of the fourth delay state 1212. Because the INT_enable signal 1330 is low during the fourth delay state 1224, the ADC of the sensor measurement circuit 525 is not integrating and / or accumulating a current count corresponding to the current through the analyte sensor 530 during the fourth delay state 1224. The counter 1434 receives the clock signal 1432 and continuously increments until a configurable absolute value defined by a parameter register 1436 is reached. Once the configurable absolute value is reached, the counter 1434 or another portion of the state machine 1430 generates a state change signal 1438 that triggers a change to the fifth delay state 1228 and a reset of the counter 1434.

[0288] At the start of the fifth delay state 1228, one of a first potential 1340 (e.g., 0 V in “store” mode, 0.60 V in “run” mode), 0 V, or an open circuit voltage (e.g., a high impedance state) is applied to the working electrode of the analyte sensor 530 and maintained for the duration of the fifth delay state 1228. During at least the rising edge 1346 of the second potential 1342, the current through the analyte sensor 530 is substantially dominated by the RC characteristics of the analyte sensor 530, such that the current substantially decays during the fifth delay state 1228. Because the INT_enable signal 1330 is low during the fifth delay state 1228, the ADC of the sensor measurement circuit 525 is not integrating and / or accumulating current counts corresponding to the current through the analyte sensor 530 during the fifth delay state 1228. A counter 1434 receives a clock signal 1432 and continuously increments until it reaches a configurable absolute value defined by a parameter register 1436. Once the configurable absolute value is reached, the counter 1434 or another portion of the state machine 1430 generates a state change signal 1438 that triggers a change to the first delay state 1206 and a reset of the counter 1434.

[0289] In some embodiments (e.g., to determine the average impedance of the analyte sensor 530 during a “run” mode in which the analyte sensor 530 is already inserted into the host's skin), the state machine 1430 may be configured to cycle through the above-mentioned states (or a subset of the above-mentioned states) a predetermined number of times (e.g., 125) over a predetermined time interval (e.g., 10-12 seconds) before the MUX 1416 is configured to pass the integrated current count value from the integrator 1414 to the sample buffer 1420 and / or to the threshold detection module 1422 for a determination of whether to generate a controller wake-up signal 1424 to wake up the controller 535. In some such embodiments, the integrator 1414 is configured to integrate the differential current count samples passed by the MUX 1412 (e.g., the integrator 1414 adds each subsequent differential current count sample to a running sum of the differential current count samples previously passed by the MUX 1412 for the integration period).

[0290] The accumulator 1414 is configured such that when the state machine 1430 cycles through the above-mentioned states (or a valid subset of the above-mentioned states) a predetermined number of times and the accumulator 1414 sums the differential current count samples generated during the predetermined number of cycles, the accumulator 1414 passes the summed differential current count value to the MUX 1416, and based on the summation enable signal 1418 being set high, the MUX 1416 passes the summed differential current count value to a sample buffer 1420 which stores the summed differential current count value.

[0291] In some such embodiments, the threshold detection module 1422 may be configured to generate a controller wake-up signal 1424 in response to the MUX 1416 passing the summed differential current count value to the sample buffer 1420, and in some cases also to the threshold detection module 1422. In such embodiments, a configurable threshold for generating the controller wake-up signal 1424 is determined by receipt and / or storage of a summed differential current count value by the sample buffer 1420. In response to the controller wake-up signal 1424, the controller 535 may be configured to wake up and further process the summed differential current count value stored in the sample buffer 1420 (e.g., by dividing the summed differential current count value by the number of differential current counts "N" to calculate an average current count value that can be utilized to calculate the average impedance of the analyte sensor 530 according to any suitable or known processing algorithm (e.g., Ohm's law, etc.). Thus, battery can be further conserved, even during run mode, by having the controller 535 sleep while the state machine 1430 determines one or more current counts and stores one or more of the current counts in the sample buffer 1420.

[0292] In some other embodiments (e.g., for determining the impedance of the analyte sensor 530 during a “storage” mode in which the analyte sensor 530 has not yet been inserted into the host's skin), the state machine 1430 may, for each cycle through the above-mentioned states (or a valid subset of the above-mentioned states), cause the MUX 1412 to pass the differential current count samples generated by the differentiator 1406 directly to the MUX 1416 during the pulse count sampling state 1220 as described above. In response to the sum enable signal 1418 being low, the MUX 1416 may pass each of the differential current count samples to a sample buffer 1420 that stores the differential current count sample. In such embodiments, the integrator 1414 may not integrate multiple differential current count samples from the differentiator 1406 and may be effectively bypassed.

[0293] Further, in some such storage mode embodiments, the threshold detection module 1422 may be configured to generate a controller wake-up signal 1424 in response to a predetermined and / or calibrated number “N” of differential current count samples stored continuously or non-continuously in the sample buffer 1420 that meet (e.g., are either greater than, less than, or equal to) a predetermined threshold (e.g., 0x7FF in hexadecimal notation) or a predetermined threshold range (e.g., within a range of 0x700 to 0x7FF in hexadecimal notation). In response to the controller wake-up signal 1424, the controller 535 may be configured to wake up and further process one or more of the differential current count values ​​stored in the sample buffer 1420 (e.g., determine whether a false wake-up occurred and / or calculate an average impedance of the analyte sensor 530 according to any suitable or known processing algorithm (e.g., Ohm's law)). If the wake-up in response to the generation of the controller wake-up signal 1424 is subsequently determined to be a false wake-up, the controller 535 may cause the analyte sensor system 308 to re-transition into the “storage” mode, and the controller 535 may then return to a lower power mode.

[0294] In some still other embodiments (e.g., during actual continuous glucose monitoring), the state machine 1430 may be configured such that all states except the pre-count sampling state 1208 are disabled, and the pre-count sample buffer 1404, the differentiator 1406, and the integrator 1414 are effectively bypassed and / or otherwise disabled. In such embodiments, the current count samples from the ADC of the AFE are passed directly to the MUX 1412. The differential mode enable signal 1410 and the sum enable signal 1418 may both be set low. Thus, in response to the differential mode enable signal 1410 being low, the MUX 1412 passes the current count samples directly to the MUX 1416, and in response to the sum enable signal 1418 being low, the MUX 1416 passes the current count samples to the sample buffer 1420, which stores each of the current count samples.

[0295] Further, in some such embodiments, the threshold detection module 1422 may be configured to generate a controller wake-up signal 1424 in response to a predetermined number "N" of current count samples being stored in the sample buffer 1420. In response to the controller wake-up signal 1424, the controller 535 may be configured to wake up and further process one or more of the current count values ​​stored in the sample buffer 1420 (e.g., calculate an analyte concentration value based at least in part on the current count values ​​according to any suitable or known processing algorithm).

[0296] In addition, the present disclosure also contemplates disabling one or more of states 1206, 1208, 1212, 1216, 1220, 1224, 1228, as previously described in connection with FIG. 12. For example, in some embodiments, the fifth delay state 1228, which may also be considered an “extended idle” state, may be enabled only when the analyte sensor system 308 is in the “storage” mode described above, where the analyte sensor 530 has not yet been disposed on the host's skin. Such an “extended idle” state may be utilized to maintain a voltage bias across the terminals of the analyte sensor 530 at 0V or open circuit to avoid oxidation and / or other sensor damage that would otherwise be caused by applying a defined non-zero voltage bias across the terminals of the analyte sensor 530.

[0297] In some embodiments, one or both of the second delay state 1212 and the fourth delay state 1224 may be disabled. For example, one purpose of the delays 1206, 1212, 1216, 1224 is to suspend measurement, sensing, and / or integration of current counts by the ADC of the AFE during the period immediately following a change in the voltage bias applied to the working electrode of the analyte sensor 530. Because the working electrode potential is held constant for the duration of each of the pre-count sample state 1208 and the pulse count state 1220, the second delay state 1212 and the fourth delay state 1224 may be unnecessary in some such implementations.

[0298] In some embodiments in which the working electrode potential is held at the same potential, e.g., 0 V, in each of the pre-count sampling state 1208 and the enabled fifth delay state 1228, the first delay state 1206 may be disabled if it would otherwise follow directly after the fifth delay state 1228 (e.g., all stages of the first delay state 1206 except for the first stage in the session), since there is no change in potential when transitioning directly from the fifth delay state 1228 to the pre-count sampling state 1208.

[0299] In some embodiments in which the working electrode potential is held at the same potential, for example 0.6 V, while taking successive analyte concentration measurements during the "run" mode described above, the count sampling state 1220 is not valid and all states except for the pre-count sampling state 1208 can be disabled since there is no change in the potential applied to the working electrode of the analyte sensor 530 and there is no transition from one state to the other. Furthermore, when the pulse count sampling state 1220 is disabled, the differential mode enable signal 1410 can be forced to a low disabled state since without the pulse count sampling state 1220, differential current count samples would not be generated or utilized.

[0300] An exemplary method 1500 for controlling an analyte sensor system is provided below in connection with FIG. 15. Method 1500 includes one or more steps or actions that may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims. Method 1500 may correspond to at least the preceding description in connection with FIGS. 12-14.

[0301] Block 1502 includes utilizing a state machine to cause a first potential to be applied across the analyte sensor during a first sampling state and a second potential to be applied across the analyte sensor during a second sampling state. For example, as described above in connection with at least FIGS. 12-14, the state machine 1430 may be configured to cause a first potential 1340 to be applied across the analyte sensor 530 during the first sampling state 1208 and a second potential 1342 to be applied across the analyte sensor 530 during the second sampling state 1220. As described above in connection with at least FIGS. 13 and 14, in a first mode of operation (e.g., a "storage" mode in which the analyte sensor 530 has not yet been inserted into the skin of a host), the first potential 1340 may be zero volts and the second potential 1342 is a predetermined amount (e.g., 16 mV) higher than the first potential 1340. In a second operating mode (e.g., a "run" mode in which the analyte sensor 530 is inserted into the host's skin), the first potential 1340 may be the same as the potential (e.g., 0.6 V) applied across the analyte sensor 530 to determine the analyte concentration in the host, and the second potential 1432 (e.g., 0.616 V) is higher than the first potential 1430 by a predetermined amount (e.g., 16 mV).

[0302] Block 1504 includes utilizing the analyte sensor measurement circuit to generate a first digital count corresponding to a first current through the analyte sensor during the first sampling state based on application of the first potential, and to generate a second digital count corresponding to a second current through the analyte sensor during the second sampling state based on application of the second potential. For example, as previously described in connection with at least Figures 13 and 14, the analyte sensor measurement circuit 525 may be configured to generate a first digital count 1402 corresponding to a first current through the analyte sensor 530 during the first sampling state 1208 based on application of the first potential 1340, and to generate a second digital count 1402 corresponding to a second current through the analyte sensor 530 during the second sampling state 1220 based on application of the second potential 1342.

[0303] Block 1506 includes utilizing a detection circuit to determine a first difference between the second digital count and the first digital count and generating a controller wake-up signal in response to at least the first difference satisfying a threshold or range of thresholds. For example, as described above in connection with at least Figures 13 and 14, the differentiator 1406 may be configured to determine a first difference between the first digital count 1402 and the second digital count 1402, and the threshold detection module 1422 may be configured to generate a controller wake-up signal 1424 in response to at least the first difference satisfying a threshold.

[0304] Block 1508 includes causing the controller to transition to a lower power state for at least the duration of the first sampling state, the second sampling state, and the determination of the first difference, transition from the lower power state to an operational state in response to a controller wake-up signal, and determine impedance of the analyte sensor based at least in part on the first difference. For example, as described above in connection with at least FIGS. 12-14, the controller 535 may be configured to transition to a lower power state (e.g., a sleep state) while the state machine 1430 cycles through the enabled states 1206, 1208, 1212, 1216, 1220, 1224, 1228. The controller 535 may be further configured to transition from this lower power state to an operational state in response to a controller wake-up signal 1424. Upon waking, the controller 535 may determine the impedance of the analyte sensor 530 based at least in part on the difference between a first digital current count 1402 corresponding to the current through the analyte sensor 530 while a first potential 1340 is applied across the analyte sensor 530 during the first sampling state 1208 and a second digital current count 1402 corresponding to the current through the analyte sensor 530 while a second potential 1342 is applied across the analyte sensor 530 during the second sampling state 1220. For example, one or more counts stored in a sample buffer 1420 (see, e.g., FIG. 14 ) may be utilized by the controller 535 upon waking to make such a determination of the impedance of the analyte sensor 530.

[0305] In some embodiments, as described above in connection with at least Figures 13 and 14, the method 1500 may further include commencing application of the first potential 1340 across the analyte sensor 530 during the delay state 1206 immediately prior to the first sample state 1208, and ceasing generation of the digital count 1402 by the analyte sensor measurement circuit 525 during the delay state 1206.

[0306] In some embodiments, as described above in connection with at least Figures 13 and 14, the method 1500 may further include commencing application of the second potential 1342 across the analyte sensor 530 during the delay state 1216 immediately prior to the second sample state 1220, and ceasing generation of the digital count 1402 by the analyte sensor measurement circuit 525 during the delay state 1220.

[0307] In some embodiments, as described above in connection with at least Figures 13 and 14, the method 1500 may further include utilizing a state machine 1430 to apply a zero potential (e.g., the first potential or an open circuit voltage) across the analyte sensor 530 during a delay state 1228 following the second sample state 1220, and interrupting generation of the digital count 1402 by the analyte sensor measurement circuit 525 during the delay state 1228.

[0308] In some embodiments, as described above in connection with at least FIGS. 13 and 14 , the method 1500 may further include storing the first digital count 1402 in a pre-count sample buffer 1404 before the differentiator 1406 determines the difference between the digital current count 1402 received from the ADC during the first sampling state 1208 and the digital current count 1402 received from the ADC during the second sampling state 1220.

[0309] In some embodiments, as described above in connection with at least FIGS. 13 and 14 , the method 1500 may further include receiving, by a differentiator 1406, a first digital count 1402 from the pre-count sample buffer 1404, receiving, by the differentiator 1406, a second digital count 1402 from the ADC, and determining a difference between the digital current counts utilizing the differentiator 1406.

[0310] In some embodiments, as described above in connection with at least Figures 13 and 14, the method 1500 may further include utilizing an integrator 1414 to generate a sum of a first difference and at least a second difference between the third digital count 1402 and the fourth digital count 1402, where the third digital count corresponds to a third current flowing through the analyte sensor 530 during a subsequent stage of the first sampling state 1208, and the fourth digital count corresponds to a fourth current flowing through the analyte sensor 530 during a subsequent stage of the second sampling state 1220.

[0311] In some embodiments, as described above in connection with at least FIGS. 13 and 14, the method 1500 may further include generating a controller wake-up signal 1424 in response to a sum of at least the first difference and the second difference satisfying a threshold value.

[0312] In some embodiments, the method 1500 may further include utilizing the controller 535 to define at least one parameter of the state machine 1430 (e.g., stored in the parameter register 1436) before transitioning to the lower power state.

[0313] Combining actuation detection methods In some embodiments, for a robust wake-up procedure and to avoid false wake-ups, a number of indicators of implantation of the analyte sensor system 530 may be used to determine when the analyte sensor system 308 should exit a lower power state. However, care should generally be taken to avoid damage or alteration of the performance characteristics of the analyte sensor system 308, to maintain robustness against humidity events that may trigger actuation prior to implantation of the analyte sensor 530, and to maintain relatively lower power operation that may be important for battery-powered devices.

[0314] In embodiments, the primary and secondary signals from the analyte sensor 530 may be used to trigger operation of the analyte sensor system 308. For example, a secondary signal generated using the analyte sensor 530, such as impedance, may be monitored and compared to a threshold or other condition. If the secondary signal achieves or meets a threshold or other condition, it may cause the analyte sensor 530 to gather information related to the level of the analyte in the host. If the level of the analyte in the host achieves a second threshold or condition, it may cause the analyte sensor system 308 to exit a lower power state. In embodiments where the potentiostat is always on, the secondary signal may be monitored to operate other circuits and subsystems of the analyte sensor system 308 to continuously or periodically cause the analyte sensor 530 to gather information related to the level of the analyte in the host.

[0315] In an embodiment, a primary signal from the analyte sensor 530 (which may be related to or used to calculate a level of an analyte in a user, as described above) may be used in combination with a secondary signal obtained using the analyte sensor 530, and / or signals from sensors or other components that may be included in or used in conjunction with the actuation detection circuit 520 and / or actuation detection component 545, to control actuation of the analyte sensor system 308 and reduce false wake-ups. In an embodiment, the primary and secondary signals from the analyte sensor 530, and / or secondary signals from sensors or other components that may be included in or used in conjunction with the actuation detection circuit 520 and / or actuation detection component 545 may be used for actuation purposes, and such analyte sensor 530 and other signals are monitored at more than one time period (e.g., from prior to implantation of the analyte sensor 530, at implantation, and at various distinct stages at which detectable events may typically occur beyond implantation). A variety of these signals may be measured / characterized at different times to provide a more robust actuation scheme.

[0316] 5 (by way of example), in an embodiment, the secondary signal from the actuation detection component 545 may indicate that the analyte sensor system 308 has been removed from the product packaging of the analyte sensor system 308 or may otherwise indicate a determination that implantation of the analyte sensor 530 and / or deployment of the analyte sensor system 308 is likely to occur in the near future, and the secondary signal from the analyte sensor 530 may indicate that implantation has occurred. For example, a secondary signal from an accelerometer or other component / switch used for actuation purposes (e.g., as described herein) may be monitored, and if the secondary signal indicates that the analyte sensor system 308 has been removed from the product packaging of the analyte sensor system 308 or that implantation of the analyte sensor 530 has occurred or is likely to occur in the near future, the analyte sensor 530 may be used to generate a primary signal related to the level of the analyte in the host. For example, the primary signal related to the level of the analyte in the host may be used to determine whether implantation of the analyte sensor 530 has occurred. If the primary signal related to the level of the analyte in the host achieves a threshold or condition, the analyte sensor system 308 may be caused to exit a lower power state. In an embodiment, a secondary signal from an accelerometer may be monitored, and another secondary signal may be monitored by a temperature sensor, a conductivity sensor, a capacitance sensor, an inductance sensor, a voltage sensor, an impedance sensor, or any other sensor capable of determining an electrical, physical, magnetic, or chemical property indicative of implantation of the analyte sensor 530 in the host.

[0317] In an embodiment, the actuation detection circuit 520 may monitor a secondary signal generated by a bridge-type switch / sensor, a pull-tab switch / sensor, an audio sensor, a proximity sensor, an RFID sensor, a magnetic field-based switch / sensor, or any other switch / sensor / approach, including those discussed herein, that may determine that the analyte sensor system 308 has been removed from the product packaging and / or applicator, or that implantation of the analyte sensor 530 has occurred or is likely to occur in the near future. For example, a secondary signal may be generated by disconnecting or connecting electrical contacts of a bridge-type switch / sensor (e.g., as described above in connection with FIG. 6C), which may indicate that the analyte sensor system 308 has been removed from the product packaging and / or applicator. In an embodiment, a pull-tab-type switch / sensor may be used to cause the analyte sensor system 308 to generate a secondary signal for actuation purposes. For example, a non-conductive material may be placed between spring-loaded electrical contacts, as discussed herein. In response to the non-conductive material between the spring-loaded electrical contacts being removed (with or without direct user intervention), the spring-loaded electrical contacts may be caused to form a physical / electrical connection that may electrically couple the contacts to one another. The secondary signal may indicate that the spring-loaded electrical contacts are connected to one another, thus initiating a wake-up.

[0318] In an embodiment, the proximity sensor may generate a secondary signal if it determines that the analyte sensor system 308 has been removed from the product packaging and / or applicator to a threshold distance. In an embodiment, the audio sensor may generate a secondary signal if an audio signature is recognized (e.g., by using a transducer and other audio components), which may indicate that the analyte sensor system 308 has been removed from the product packaging and / or applicator, or that implantation of the analyte sensor 530 has occurred or is likely to occur in the near future. Similarly, the secondary signal may be generated using an RFID sensor, a magnetic field sensor, or any other sensor capable of determining that the analyte sensor system 308 has been removed from the product packaging and / or applicator, or that implantation of the analyte sensor 530 has occurred or is likely to occur in the near future.

[0319] In an embodiment, a primary signal related to the level of analyte in the host may be generated using analyte sensor 530 after a secondary signal, which may be indicative of analyte sensor system 308 being removed from the product packaging and / or applicator, is detected using one or more of operation detection component 545 and operation detection circuit 520. The level of analyte in the host and a threshold or other condition / characteristic that may be indicative of implantation of analyte sensor 530 may be used to determine whether implantation of analyte sensor 530 is likely to occur.

[0320] For example, the secondary signal may be generated using a temperature or pressure sensor. If the secondary signal generated by the temperature / pressure sensor achieves a threshold or condition, the analyte sensor system 308 may be triggered to exit a lower power state. In this example, the threshold condition may be a temperature related to the average body temperatu...

Claims

1. 1. An analyte sensor system for controlling operation of analyte sensor electronics, comprising: an analyte sensor that is electrically and mechanically coupled to analyte sensor electronics prior to transitioning the system to an operational state; the analyte sensor electronics comprising: generating a trigger for the system to exit the lower power state and transition to the operational state, the trigger being based on a threshold associated with a deployment of the system; generating a control signal in response to the trigger operable to cause the analyte sensor to collect information related to a level of an analyte in a host; generating a comparison between the information relating to the level of the analyte in the host and a condition; and adapted to: The system exits the lower power state and transitions to the operational state based on the trigger and the comparison indicating that the level of the analyte in the host satisfies the condition.

2. The system of claim 1 , wherein the analyte sensor electronics is further adapted to generate the trigger to the system in response to the threshold being satisfied for at least a predetermined time.

3. 2. The system of claim 1, wherein the trigger is a signal generated using one or more of an actuation detection circuit and an actuation detection component adapted to detect one or more of an insertion of the analyte sensor into the host and a deployment of the system.

4. 2. The system of claim 1, wherein the control signal is a signal operable to cause a potentiostat to apply a voltage bias to the analyte sensor, thereby causing the analyte sensor to collect the information related to the level of the analyte in the host.

5. The system of claim 1 , wherein after the system transitions to the operational state, the system continues to collect information related to the level of the analyte in the host and communicates the information to one or more display devices or one or more partner devices.

6. The system of claim 1 , wherein the threshold value is related to a level of a known analyte normally present in a human host.

7. The trigger is a detected proximity between the analyte sensor electronics and a reference object; a temperature monitored using the analyte sensor electronics; and an accelerometer output of the analyte sensor electronics; and a response generated using wireless signaling transmitted or received by the analyte sensor electronics; a detected change in air pressure measured by the analyte sensor electronics; and audio information monitored by the analyte sensor electronics; and a signal generated by the analyte sensor electronics in response to photons detected by the analyte sensor electronics; a conductivity measured between two terminals of the analyte sensor electronics; and a mechanical switch located on or within the housing of the analyte sensor electronics; a component adapted to change a connection between two conductive elements of the analyte sensor electronics in response to movement of the component; The measured distortion; The system of claim 1 , wherein the image is generated using one or more of:

8. The system of claim 1 , wherein the system exits the lower power state based on a determination that the level of an analyte in a host exceeds a threshold value.

9. The system of claim 1 , wherein the analyte sensor electronics is further adapted to generate the trigger in response to a condition being met at a programmed time interval.

10. 2. The system of claim 1, wherein information related to the level of the analyte in the host is used to generate a detected count, the condition includes a threshold characteristic of the count, and when the comparison indicates that the detected count has reached the threshold, the system exits the lower power state and transitions to the operational state.

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