Control system for wireless charging and alignment

Abstract

A system for wirelessly charging an implantable device is described. The system can include an estimation device or component that estimates a field strength at a receiving coil of an implantable device based on electrical signals available within the implantable device. The system can also include a control system to vary a strength of a charging field generated by a charger. The system can also be used to align a wireless charger with an implantable device for charging a battery of the implantable device. Methods and devices for implementing the charging system are also described.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 798,055, filed January 29, 2019, entitled “Control System for Wireless PowerCharging and Alignment,” the entirety of which is incorporated herein by reference. Technical Field

[0003] This application generally relates to control systems for wireless charging and alignment. Background Technology

[0004] Implantable devices, such as those implanted in the body of an individual or other organism, can be used for a wide range of functions. For example, neuromodulation devices can be implanted to treat a wide variety of diseases. As another example, brain-computer interfaces can be implanted to enhance and / or repair various cognitive and sensorimotor functions. Yet another example is miniature sensors used to sense an individual's physiological parameters. These and other implantable devices can include various subsystems for collecting data, providing output based on the collected data, performing calculations, and / or implementing various commands. Once an implantable device is placed inside a user, its battery cannot be easily replaced.

[0005] Various technologies and systems exist for powering implantable devices. One technology involves providing power to implantable devices via wireless power transmission that utilizes electromagnetic waves. Most conventional systems use near-field induction coils to charge the battery of the implantable device. Summary of the Invention

[0006] Various examples are described relating to the charging and alignment of a wireless charger with an implantable device, systems for the charging and alignment of a wireless charger with an implantable device, and methods for the charging and alignment of a wireless charger with an implantable device. The methods, systems, and examples described below relate to closed-loop charging and alignment of an implantable device using a wireless charger that utilizes an electromagnetic (“EM”) field.

[0007] In an example, a system is described. The system includes an implantable device having a field estimator to estimate a current or estimated EM field value and a target EM field value or strength required for a battery of the implantable device to charge in relation to a strength of a charging field at the implantable device. The implantable device also includes a communication device to transmit the current and target EM field values to a charger. The system also includes a wireless charger including a communication device, an EM field driver, and a controller. The communication device communicates with the implantable device and receives the EM field values. The controller uses the EM field values to alter or control the EM field driver. The controller is designed such that the EM field driver adjusts the charging EM field until the current or experienced EM field value at the implantable device and the target EM field value match or are as close as reasonably possible.

[0008] In another example, a method is described. The method includes measuring or detecting a set of electrical parameters or values within an implantable device, estimating a current EM field value based on the set of electrical parameters, estimating a target EM field value for charging a battery of the implantable device based on the set of electrical parameters, and controlling an EM field driver of a wireless charger based on the current EM field value and the target EM field value. In some examples, the current EM field value, or current estimated value, and the target EM field value, or target EM field strength, include field information related to the EM field.

[0009] In another example, a method for aligning a wireless charger with an implantable device is described. The method includes generating a beacon or alignment EM field from an EM field driver at the wireless charger, receiving or detecting the beacon EM field at the implantable device, determining that the wireless charger is capable of generating a charging EM field, and generating a notification related to the determination. The method also includes determining that the wireless charger is capable of generating the charging EM field based on a predetermined maximum electrical parameter of the charger, such as a predetermined maximum voltage, a detected or current beacon EM field value at the implantable device, a target EM field value for charging, and a beacon electrical parameter of the charger corresponding to the beacon EM field.

[0010] In another example, a method for estimating an EM field at an implantable device is described. The method includes determining a voltage and a current at a rectifier of the implantable device. The voltage and current are compared to or used in conjunction with an electrical model or simplified electrical model of the implantable device that represents a relationship between the rectifier voltage and current and a detected or experienced EM field value. The method also includes estimating a current or experienced EM field value based on the comparison of the current and voltage at the rectifier to the electrical model, which is a scalar that indicates a strength of the EM field at the implantable device. The method also includes transmitting the current EM field value to a wireless charger or a controller associated with the wireless charger.

[0011] The reference to the illustrative examples is intended to provide examples to assist in understanding the disclosure. The illustrative examples are discussed in the Detailed Description section below. Advantages offered by various examples can be further understood by examining the specification. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more implementations and together with the description, explain the principles and implementations of the specific examples.

[0013] Figure 1 A wireless charging system for charging an implantable device is illustrated in accordance with at least one example.

[0014] Figure 2 An implantable device is illustrated in accordance with at least one example.

[0015] Figure 3 A block diagram depicting a wireless charging system is illustrated in accordance with at least one example.

[0016] Figure 4 A block diagram depicting a wireless control system of a wireless charging system is illustrated in accordance with at least one example.

[0017] Figure 5 An electrical model of an implantable device is illustrated in accordance with at least one example.

[0018] Figure 6 A graph representing data from an electrical model of an implantable device is illustrated in accordance with at least one example. Figure 5

[0019] Figure 7 A block diagram of a control system for an implantable device charger is illustrated in accordance with at least one example.

[0020] Figure 8 An example process for controlling a charger of an implantable device is illustrated in accordance with at least one example.

[0021] Figure 9 An example process for aligning a wireless controller and an implantable device for charging is illustrated in accordance with at least one example. DETAILED DESCRIPTION

[0022] ​Examples are described herein in the context of wireless charging and power supply of implantable devices. Those of ordinary skill in the art will realize that the following description is illustrative only and is not intended to be limiting in any way. For example, the control and alignment systems described herein can be used with a variety of wireless chargers, although inductive charging devices are described for convenience. Implementations of the examples illustrated in the figures will now be described in detail. Like numbers refer to like elements throughout the several views and the following description.

[0023] For the sake of clarity, not all of the routine features of the examples described herein are shown and described. It will of course be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions will be made to achieve the developer's specific goals, such as compliance with application- and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Without intent to limit the scope of what can be claimed, the examples described herein are intended to be illustrative only.

[0024] Implantable devices include mechanical, electrical, and drug stimulators, and typically use electrochemical cells or batteries as energy to cause the desired stimulation. Rather than requiring removal and replacement of expired batteries through surgery, wireless charging systems can supply energy to implantable devices equipped with chargers, recharging the batteries. In a wireless charging system, the charger or energy source includes a charging coil configured to inductively transfer wireless energy by inducing a voltage in a receiving coil of the implantable device. Wireless charging, and in particular inductive charging, typically requires a small distance, e.g., a few centimeters, between the charger and the device to be charged, but allows the implantable device to be recharged without surgery or removal from the user's body. Because of the short-range charging distance, and since charging is faster and more efficient when the wireless charger and implantable device are properly aligned, it is advantageous to properly align the two when charging.

[0025] The systems described herein provide closed-loop wireless charging to implantable devices. The closed-loop wireless charging system includes an implantable device, a wireless charger such as the inductive charger described above, and a controller connected to the wireless charger. In some examples, the controller is included within the same unit as the wireless charger. The implantable device estimates the strength of the received electromagnetic ("EM") charging field using known electrical parameters or signals within the implantable device. For example, the implantable device includes a rectifier to rectify the received EM energy, and the implantable device estimates the strength of the EM field by using a model of the implantable device and the voltage and current at the rectifier.

[0026] In an illustrative example, the implantable device is configured to estimate the strength or level of the EM field at the implantable device using electrical signals available within the implantable device, such as voltage and current values through the rectifier of the implantable device. The field estimator estimates not only the current or actual / detected EM field value, but also a target EM field value for charging the battery of the implantable device. The field estimator calculates a target EM field at the receiving coil of the implantable device, which represents a target strength of the charging EM field, such as a charging EM field value, based on the current battery voltage or charge and other factors, such as charging overhead and charging current values. The implantable device also includes a communication device that can be used to communicate the current and target EM field values from the implantable device to a controller (e.g., a component of the wireless charger). The controller is equipped to receive the current and target EM field values. With these current and target EM field values, the controller controls the EM field driver to produce an EM field that results in a current EM field value that matches the target EM field value. The controller limits, controls, or sends a signal that instructs the wireless charger to control at least one electrical parameter of the EM field driver to affect and control the EM field produced by the EM field driver.

[0027] In a second illustrative example, a system and method for aligning a wireless charger with an implantable device after the implantable device is implanted in a user is described. The system and method involve the user placing the wireless charger near the location of the implantable device and moving the wireless charger in response to a notification or feedback from the system to align the wireless charger relative to the implantable device for charging. The implantable device includes a field estimator as described above to estimate current and target EM field values based on current and voltage values within the implantable device and to send the current and target EM field values to a controller. The controller and / or wireless charger contains a processor, microprocessor, other circuitry, and / or software to determine, based on the current current level supplied to the EM field driver and the current EM field value, whether the EM field driver is capable of producing an EM field that will cause the current EM field value to match the target EM field value without exceeding a threshold current level at the EM field driver. If the controller determines that it is capable of delivering the required EM field, then a notification is generated that indicates that the wireless charger and implantable device are aligned for charging. If the controller determines that it is not capable of producing the EM field, then the user can continue to move the wireless charger searching for a location where the controller determines that it is capable of delivering the required charging EM field. In any case, the controller is also configured to provide a notification for a location where the wireless charger can come closest to meeting the field criteria for charging after a predetermined period of time has elapsed without the wireless charger being aligned.

[0028] Examples described herein provide benefits for wireless charging systems of implants. In some examples, controlling the wireless charger can result in power savings because the wireless charger and wireless field driver can be controlled to produce an EM field with a strength just enough to charge the implantable device battery without wasting additional energy. Another benefit of the controlled wireless charger is a reduction in heat buildup due to eddy currents induced in the metal can of the implantable device by the EM field. Examples, systems, and methods described herein also maintain a compact implantable device footprint or size while providing additional benefits and efficiencies, some of which are described above. The field estimator and controller can use or be directly connected to electrical components of the implantable device to detect signals and determine estimated EM field values and target EM field values without the need to introduce or add additional voltage or current sensors, although additional sensors such as current and voltage detection circuits can be included in some examples.

[0029] These illustrative examples are given to introduce the general reader to the general subject matter discussed herein and are not intended to limit the scope of the disclosure. The following sections describe various additional non-limiting examples of control and alignment systems or methods for wireless charging of implantable devices.

[0030] Referring now to Figure 1 , a system 100 for wireless charging of an implantable device 102 with a charger controller 106 and a wireless charger 104 is shown. The implantable device 102 communicates with the charger controller 106 over a communication channel 110. The communication channel 110 between the implantable device 102 and the charger controller 106 can include short-range communication over a short-range communication channel such as a Bluetooth or Bluetooth Low Energy (BLE) channel. In some examples, communicating with short-range communication such as a BLE channel can provide advantages such as consuming less power, being able to communicate across a modest distance, being able to detect proximity levels, enabling high levels of security based on encryption and short-range, and not requiring pairing for inter-device communication. The implantable device 102 can already be configured to communicate with external devices, and the communication channel 110 can be a communication channel that the implantable device typically uses.

[0031] The charger controller 106 can be a separate and distinct device from the wireless charger 104, or can be constructed in the wireless charger 104. In any case, the charger controller 106 is able to communicate with the wireless charger 104 to control the EM field 108 produced by the wireless charger 104. As an example, the EM field 108 is an EM field produced by an EM field driver or coil within the wireless charger 104.

[0032] The implantable device 102 communicates with the charger controller 106 via a communication channel 110. For example, the implantable device 102 can send data and information related to its operation (e.g., electrical signals of the implantable device 102) to the charger controller 106. The charger controller 106 can use the data and information to control and / or adjust the EM field 108, for example, to reduce wasted energy, prevent heating of the implantable device, and ensure proper alignment and charging of the battery within the implantable device 102.

[0033] Figure 2 An example of an implantable device 102 for use with the systems and methods described herein is shown in accordance with at least one example. The implantable device 102 includes a canister 150 containing therein electronics, processors, circuitry, and other components for implementing the purposes of the implantable device 102. For a neuromodulation device, the electronics, processors, circuitry, and other components inside the canister 150 are configured to deliver electricity or a pharmaceutical agent or stimulation to a target area in a user. In some examples, the canister 150 shields the components disposed therein. Thus, the canister 150 can be formed of or include a metal or other shielding material or arrangement, such as a metal mesh that can provide a Faraday cage. The charging coil, communication device, and other components that must remain unshielded can be disposed within a container 152, which can be formed of a non-metallic material such as plastic.

[0034] In conventional implantable devices and charging systems, electrical interference and / or overheating can occur when the charger provides a stronger charging field than is needed to charge the implantable device. For example, the EM field generated by the wireless charger can create eddy currents in the canister 150 of the implantable device and can heat the canister, causing discomfort to the user and potentially damaging the implantable device.

[0035] The systems described herein control the charger in a way that conserves energy resources and uses energy sources efficiently. This is achieved, at least in part, by the charger controller 106 controlling the wireless charger 104 to generate an EM field 108 that takes into account the conditions in which the implantable device 102 exists. Thus, the strength of the EM field 108 is selected to be sufficient to charge the battery of the implantable device 102 and to mitigate or eliminate energy waste and loss and prevent heating of the canister 150.

[0036] Because the implantable device 102 is intended to be implanted inside a user's body, it is beneficial to keep the size and / or footprint of the implantable device 102 as small as possible. Such size constraints preclude, among other things, the use or inclusion of additional components to perform tasks such as magnetic field or charging field detection, presumably due to the associated increase in size or footprint of the implantable device 102. For example, an EM field detector can be implemented to complete field strength measurements and relay to the charger controller 106 for controlling the wireless charger 104 and EM field 108, however, additional components such as a field detector take up space and can increase the footprint of the implantable device 102. The systems and methods described herein solve the footprint problem by utilizing electrical signals contained within the implantable device to estimate EM field strength based on an electrical model of the implantable device 102 and without increasing the size of the implantable device 102.

[0037] Figure 3 A diagram of an example wireless charging control system 101 including an implantable device 102 and a wireless charger 104 is shown in accordance with at least one example. Generally, the implantable device 102 includes components typical of a neuromodulation device as well as power, charging, and communication systems. Generally, the wireless charger 104 includes a power source, a control system, a communication system, an EM field driver, and an induction coil for generating a charging field.

[0038] The implantable device 102 includes a receiving coil 138, a rectifier 112, an overvoltage protection shunt 114, a linear battery charger 116, a battery 118, an implantable device controller 120, and an implantable device communication device 122. The receiving coil 138 receives a transmitted charging field, such as an EM field, which induces a current in the receiving coil 138. The rectifier 112, which is electrically connected to the receiving coil 138, receives the alternating current induced in the receiving coil 138 and converts the current to direct current that is more suitable for charging the battery 118 of the implantable device 102. The rectifier 112 can include several components in a rectification circuit, such as those shown and described below with respect to Figure 5

[0039] The overvoltage protection shunt 114 is provided for situations in which the input voltage exceeds a maximum or threshold voltage at the rectifier 112. This can occur due to an EM field that is too strong, generated by the wireless charger or by other conditions (e.g., short circuit). The rectifier 112 provides direct current to the linear battery charger 116, which charges the battery 118 of the implantable device 102.

[0040] ​The implantable device controller 120, which can control the functions of the implantable device 102 and perform the methods and tasks described herein, receives input from the rectifier 112, the linear battery charger 116, and the implantable device communication device 122. The implantable device controller 120 can use these inputs to estimate a current EM field value and a target EM field value. The current EM field value represents the EM field experienced at the receiving coil 138. The target EM field value represents the EM field value needed or desired to charge the battery 118. The methods and processes for determining the current EM field value and the target EM field value are discussed below with reference to Figure 5 and Figure 6 The methods and processes for determining the current EM field value and the target EM field value are discussed below with reference to

[0041] Finally, the implantable device communication device 122 is configured to communicate with the charger communication device 124 over a communication channel (e.g., the communication channel 110) to convey the current and target EM field values and other data or information related to the alignment or functioning of the implantable device 102. For example, the implantable device communication device 122 can include a transceiver capable of receiving and transmitting data with the charger communication device 124 and / or other communication devices. In some examples, the implantable device communication device can be a BLE antenna, or other short-range communication antenna.

[0042] In one example, the implantable device controller 120 and / or the charger controller 106 can include one or more processors. The processors include computer-readable media, such as random access memory (RAM) coupled to the processor. The processors execute computer-executable programs stored in memory, such as executing one or more computer programs. Such processors can include a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), field programmable gate arrays (FPGAs), and state machines. Such processors can further include programmable electronic devices such as PLCs, programmable interrupt controllers (PICs), programmable logic devices (PLDs), programmable read-only memories (PROMs), electronically programmable read-only memories (EPROMs or EEPROMs), or other similar devices.

[0043] Such a processor can include or be in communication with a medium that can store instructions for execution by the processor, such as a non-transitory computer-readable medium. Examples of non-transitory computer-readable media can include but are not limited to electronic, optical, magnetic, or other storage devices capable of providing a processor, such as a processor in a web server, with computer- readable instructions. Other examples of media that can be used in the role of

[0044] As introduced herein, Figure 3 The wireless charging control system 101 is also shown to include a wireless charger 104 that includes a charger controller 106. Blocks shown within the dashed line that make up the implantable device 102 and / or the wireless charger 104 represent elements or objects that are typically contained within each respective component. Each component of the implantable device 102 and the wireless charger 104 is simplified and represented by individual blocks or elements, although each component can include multiple parts or components and / or one physical object or component can perform the tasks or functions associated with one or more blocks. However, it should be understood that because certain components are shown within a common dashed line boundary, it is not required that these components be part of the same physical device. Rather, components of the implantable device or the wireless charger 104 can be incorporated into one or more separate devices. For example, as shown, the charger controller 106 and the wireless charger 104 can be separate discrete devices. Figure 1

[0045] The wireless charging control system 101 is shown as a simplified block diagram including components typically contained within the implantable device 102, such as a receive coil 138, a rectifier 112, an overvoltage protection shunt 114, a battery 118, a linear battery charger 116, an implantable device controller 120, and an implantable device communication device 122. A charger communication device 124 is in communication with the charger controller 106 to communicate with the implantable device 102 (e.g., via the implantable device communication device 122). For example, such information can relate to current and target EM field values from the implantable device 102, alignment data, or other information.

[0046] ​The wireless charger 104 also includes a power management system 126 and an EM field driver 128. The power management system 126 is configured to regulate the power or current flowing to the EM field driver 128 and the transmit coil 140. The EM field driver 128 is configured as an inductive single coil or multi-coil charger. In some examples, the EM field driver 128 and the wireless charger 104 can be a wireless charger that complies with standards known to those of skill in the art. In some other examples, these standards can include or be similar to the Qi inductive standard, the A4WP standard, the PMA standard, or any other appropriate standard related to wireless charging, with or without field regulation standard methods. The wireless charger 104 can operate at frequencies in the range of 110-205 kHz. In other examples, the wireless charger 104 can also be a magnetic resonance charger or other form of wireless charging, such as ultrasonic charging. The wireless charger 104 can be powered by a power source 130, such as a battery or other power source, such as a USB-c or other wired power source.

[0047] The charger controller 106 is configured to control or alter the electrical signal or power to the power management system 126. For example, the charger controller 106 can increase or decrease the current flowing at or through the power management system 126. For example, the charger controller 106 can instruct the power management system 126 to provide a greater or lesser level of current to the EM field driver 128. The change in current to the EM field driver 128 causes the strength of the EM field generated by the EM field driver 128 to increase or decrease.

[0048] Figure 4 An example wireless charging control system 101 is shown in accordance with at least one example. In this example, the implantable device 102 includes similar elements as those described above with respect to Figure 3 the overvoltage protection shunt 114, the rectifier 112, the receive coil, the linear battery charger 116, the battery 118. Figure 4 The implantable device 102 is also shown to include an electronic load 134, which can be a circuit, programming, processor, or other component to implement the primary function of the implantable device 102, such as neuromodulation. The implantable device 102 also includes a field estimator 132, which can also be configured with communication capabilities, or can communicate with the communication device 122 as described above.

[0049] The field estimator 132 can be part of the implantable device controller 120 described above, or can be a separate component. In one example, the field estimator 132 is implemented functionally by a portion of the implantable device controller 120 to avoid introducing additional components or elements into the implantable device 102. The field estimator 132 uses current and voltage values from the rectifier 112 or other components of the implantable device 102 to estimate a current EM field value representative of the strength of the charging EM field at the receiving coil 138. The field estimator 132 further uses the voltage of the battery 118, the current battery voltage, and the charging current value to estimate a target EM field value representative of a target strength of the charging EM field, such as the charging EM field value at the receiving coil 138. The wireless charger 104 with the charger controller 106 is configured to control the EM field driver 128 to vary the EM field strength, and to cause the current EM field value to approximate and / or equal the target EM field value at the receiving coil 138. In some examples, this can be achieved through continuous feedback and input from the field estimator 132. The feedback and input from the field estimator can be received or transmitted at different rates, for example in some cases the feedback can be transmitted from the implantable device communication device at a rate of approximately 10 samples / second. Other sampling rates are contemplated and will be understood and appreciated by those skilled in the art. In some examples, the sampling rate can vary from approximately 100 samples / second to several seconds per sample. The charger controller 106 can also include the power management system 126 described above in Figure 3

[0050] The charger controller 106 is also configured to implement an alignment process based on data received from the field estimator 132. Specifically, the charger controller 106 is configured to compare the current level of current flowing to the transmitting coil 140 via the EM field driver 128 to the current EM field value at the receiving coil 138 estimated by the field estimator 132. The charger controller 106 is further configured to use this comparison to infer whether the wireless charger 104 is capable of producing an EM field that causes the current EM field value at the implantable device 102 to be at least equal to the target EM field value. The charger controller 106 is configured to make this inference based on the current location of the wireless charger 104 and the maximum or threshold current compared to the current being delivered to the EM field driver 128. This can be used as part of an alignment system for the wireless charger 104 and the implantable device 102 to ensure proper alignment for efficient charging. The wireless charger 104 can be considered substantially aligned with the implantable device 102 when the wireless charger 104 is capable of producing a field as described above.

[0051] ​For example, the wireless charger 104 also includes a notification device 136 to provide a notification to a user of the system that the wireless charger 104 is in a position or location suitable for charging. The notification device 136 can also notify the user that the position or location is not suitable for charging or to continue moving the wireless charger 104 to find a suitable position. In some cases, the notification device can indicate to the user that the current position can be sufficient to meet a "best effort" charging mode described below, but can not be sufficient to provide an EM field that produces a target current and voltage at the rectifier of the implantable device 102.

[0052] Figure 5 A simplified electrical model 200 of the implantable device 102 that can be used to determine the current EM field value as described above is shown in accordance with at least one example. The electrical model 200 is a simplified model of the implantable device 102 that shows a representative voltage source 202 that represents the voltage induced in the receive coil 138, a coil 210 for the inductance of the receive coil 138, and a resistor 208 for the resistance of the receive coil 138. This electrical model is simplified and thus does not represent every component of the implantable device, but is used to provide a simplified model that can be used to calculate a value for the representative voltage source 202. The value V H is related to the magnetic field (typically represented as the vector H) and is associated with the representative voltage source 202, which is directly proportional to the strength of the EM field coupled to the receive coil 138. V H Thus serves as a variable for the strength of the EM field received by the receive coil 138 (sometimes referred to as the received EM field strength), which is the same field produced by the EM field driver 128. V H The value of V

[0053] Some of the components of the electrical model 200 represent other components of the implantable device, such as the rectifier 112. A voltage value associated with the rectifier 112 can be measured or detected between the node voltage 206 and the signal ground 212. In addition, the current source 204 represents the current I rectifier at the rectifier 112 or through the rectifier 112. I rectifier may include or be determined based on a battery current, which represents the current flowing at the battery 118, and an overvoltage protection shunt current, which represents the current flowing to the overvoltage protection shunt 114. I rectifierThe values of V can be determined by any method or technique commonly used to solve or resolve unknown values within a circuit. For example, node voltage method and mesh current method can be used to analyze the simplified electrical model 200. Some signals, such as battery current, shunt current, and rectifier voltage, can be known signals within the implantable device 102 and already monitored, measured, or otherwise known by the implantable device controller 120, for example, for maintenance or monitoring of the implantable device. Using the electrical model 200 to determine V H One benefit is that additional components do not have to be added to the implantable device 102, thereby maintaining a footprint as small as possible.

[0054] The electrical model 200 can be used, directly or indirectly, with the known signals, rectifier current and rectifier voltage, to determine V H . The electrical model can be input into a software program or otherwise programmed into memory to provide continuous monitoring and output of V H based on instantaneous and / or historical data of the rectifier voltage and current. In some examples, the electrical model 200 can be used to generate a data set or table of V H values for various combinations of rectifier voltage and current. For example, the electrical model 200 can be used to generate a Simulated Program with Integrated Circuit Emphasis (SPICE) simulation to generate data that can be used with the systems and methods described herein. In other examples, experimental observation and / or analytical methods can provide a model or data for use with the methods and systems herein.

[0055] Figure 6 A graph 300 is shown that displays data representing V H as a result of rectifier current 302 and rectifier voltage 304 values, according to at least one example. The data displayed in the graph 300 is generated or calculated using the electrical model 200 of Figure 5 . For example, with known capacitance, resistance, and inductance values of the additional elements of the electrical model 200, the values of I rectifier at the current source 204 and the voltage at the location 206 are input to the model and used to solve for V H values. Each line or data set 306 is associated with a different estimated V H value. The estimated or determined V H may be performed by one or more processors of the implantable device, such as the implantable device controller 120. In some examples, the estimated V HThe target EM field values, rather than raw data, are communicated to the wireless charger 104. In addition, target EM field data (described below) is communicated rather than raw data to allow for interchangeability of the wireless charger. For example, by communicating only a scalar representing the EM field strength and a scalar representing the target EM field strength, any charger can be equipped with a controller to adjust or control the EM field driver 128.

[0056] The electrical model 200 and chart 300 are also used to determine or estimate the target EM field values V HTarget . The electrical values used to determine V HTarget include the current voltage of the battery 118, an overhead voltage (which can be static or dynamic), and a charging current. The overhead voltage and charging current can be predetermined or preselected based on desired charging parameters. After the rectifier voltage 304 and rectifier current 302 parameters are collected, the same data, chart, or model can be used by the field estimator 132 to determine or estimate V HTarget .

[0057] After the field estimator 132 estimates V H and V HTarget , the implant communication device 122 communicates or sends the V H and V HTarget values to the charger communication device 124 and the charger controller 106. The charger controller 106 uses the V HTarget and V H values to control the input to the EM field driver 128 using conventional control architectures or systems.

[0058] Figure 7 is an example controller 400 that can be used with the systems and methods described herein. The controller 400 is one example of the controller 106. The structure and implementation of the controller 400 is the same as a conventional controller within a system. The inputs to the control portion 406 include V HTarget 402 and V H 404. V HTarget is the desired setpoint of the controller, and V H is the measured process value. V HTarget and V HThe difference between the two is an error value to which the control portion 406 applies proportional, integral, and differential correction terms in the case of a proportional, integral, and differential controller ("PID"). The control variable output by the control portion 406 is passed through a saturation block 408 to ensure that the output is limited to the possible range of control variables. The control variable determines or controls the current level delivered from the power supply 130 to the EM field driver 128. At block 410, the wireless charger 104 generates the EM field 108 using the controlled current level described above, and a new V HTarget and V H values are continuously fed into the controller 400. Although a PID controller has been described above, other control systems can be implemented in place of the controller shown, including neural networks, proportional, proportional-integral, differential, integral, or any other appropriate available control system. Figure 7

[0059] The controller 400 described above can be implemented as a stand-alone unit, or can be included within or connected to the wireless charger. The controller 400 can provide a signal to the wireless charger to alter the current or voltage supplied to the EM field driver. In other examples, the controller 400 can directly limit, increase, decrease, or otherwise control the current or voltage supplied to the EM field driver. In any embodiment or example described herein, the charger controller 106 should be understood to include both a stand-alone controller 400 in communication with the wireless charger, and a wireless charger that incorporates or is connected to the controller 400.

[0060] The systems described above, or comparable or otherwise equivalent systems or structures apparent to those skilled in the art, can implement several processes or methods.

[0061] Figure 8 and Figure 9 Example flowcharts illustrating processes 800 and 900 are illustrated in accordance with this specification. These processes, as well as any other appropriate processes described herein, are illustrated as logical flowcharts, the operations of which represent a sequence of operations that can be implemented in hardware, computer instructions, or a combination thereof. In the context of computer instructions, the operations can represent sequences of instructions stored as computer-executable instructions on one or more non-transitory computer-readable storage media that, when executed by one or more processors, perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, components, data structures, and the like that perform particular functions or implement particular data types. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described operations can be combined in any order and / or in parallel to implement the processes.

[0062] ​Furthermore, some, any, or all of the processes described herein may be executed under the control of one or more computer systems configured with specific executable instructions and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more applications) that executes generally on one or more processors, implemented in hardware, or implemented by a combination of these. As described above, the code may be stored on a non-transitory computer-readable storage medium, for example, in the form of a computer program, comprising multiple instructions executable by one or more processors.

[0063] Figure 8 A block diagram of a process 800 for controlling a wireless charging system, based on at least one example, is shown. The process begins at block 802, where an implant controller measures or otherwise detects electrical parameters of the implantable device 102. In some examples, an implantable device controller 120 measures or otherwise detects electrical parameters of the implantable device 102. In some examples, the implantable device controller 120 may be directly connected to a rectifier 112 to detect or determine electrical parameters at the rectifier 112, such as current and voltage. In some other examples, the implantable device controller may be connected to voltage and current sensors that measure or determine the current and voltage at the rectifier 112. Some parameters that can be determined or measured include, for example, battery voltage, battery charging current, battery voltage overhead, shunt current, battery current, and rectifier voltage.

[0064] At block 804, process 800 estimates the current EM field value at the implantable device. In some examples, the implantable device controller 120 utilizes software modules, data tables, tables of information or data, graphs, or electrical models as described above to estimate the current EM field value. For example, the implantable device controller may include a field estimator that uses a simplified electrical model, such as... Figure 5 The electrical model in the circuit is used to perform circuit analysis, such as mesh current analysis, nodal voltage analysis, or any other suitable method known to those skilled in the art for performing circuit analysis. In some other examples, the field estimator 132 uses software modules and / or other methods described herein to estimate the current EM field value. In some examples, the current EM field value is estimated at the receiving coil 138. The current EM field value may include, for example, a scalar representing the amplitude of the EM field 108 at the receiving coil 138.

[0065] At block 806, process 800 includes determining a target EM field value at implantable device 102. In some examples, implantable device controller 120 and / or field estimator utilize software, data tables, graphs, or electrical models as described above to estimate the target EM field value. For example, the implantable device controller may include a simplified electrical model, such as... Figure 5The field estimator of the electrical model in the device performs circuit analysis, such as mesh current method, nodal voltage method, or any other suitable method known to those skilled in the art for performing circuit analysis. In some examples, the target EM field value can be determined or calculated by detecting the voltage of battery 118 and adding a charging overhead, which can be predetermined. The target EM field value represents the target amplitude of the EM field 108 at the receiving coil 138. The target EM field value is based on the desired charging parameters of battery 118, which can be predetermined and include charging current and battery overhead voltage. The voltage of battery 118 is also used to determine the target EM field value. The implantable device controller 120 estimates V using the method described above. HTarget Values. Blocks 804 and 806 can be swapped to execute in reverse order in some examples. Furthermore, blocks 804 and 806 can be executed simultaneously by the implantable device controller.

[0066] At block 808, process 800 includes sending the current EM field value and the target EM field value to the controller of the wireless charger (e.g., charger controller 106) to control the EM field driver to generate a charging field. The transmission from the implantable device to the controller can be accomplished via short-range communication such as BLE.

[0067] At block 810, process 800 includes controlling the EM field driver to generate a charging field. In some examples, charger controller 106 controls or regulates the current and / or voltage supplied to EM field driver 128. Target EM field value and current EM field value, V HTarget and V H This is used to control the EM field driver 128. Block 808 may include multiple sub-processes. For example, the implantable device controller 120 transmits V via the implantable device communication device 122. HTarget and V H The signal is transmitted to the charger communication device 124, and the charger communication device 124 transmits V. HTarget and V H The signal is transmitted to the charger controller 106 to control the EM field driver 128.

[0068] Process 800 is an iterative process that is repeated at startup or throughout the entire charging cycle. V HTarget and V H The value is re-estimated at implantable device 102 by implantable device controller 120, for example at a rate of 1 Hz or close to 1 Hz, and updated. It is then communicated to charger controller 106 via implantable device communication device 122 and charger communication device 124 for use in controlling the current to EM field driver 128. In some examples, V HTarget and V HThe sampling rate of the value can be faster or slower than 1 Hz, depending on the power fluctuations at the load.

[0069] Figure 9 A block diagram of a process 900 for aligning and initiating charging of an implantable device, based on at least one example, is shown. Process 900 begins at block 902 by generating a beacon field. The beacon field is generated using a beacon current through an EM field driver 128 and a transmitting coil 140. The EM field driver 128 of the wireless charger 104 generates the beacon field. The beacon field is an EM field, which typically has low power or intensity and is not intended for charging the battery of the implantable device, although a field of full power or intensity is also possible.

[0070] Block 904A, process 900 includes receiving a beacon EM field value from implantable device 102. The beacon EM field value is transmitted by implantable device communication device 122 to charger communication device 124. The beacon EM field value is relayed from charger communication device 124 to charger controller 106. The beacon EM field value is determined as described herein and may be estimated by field estimator 132 and / or implantable device controller 120.

[0071] At block 904B, process 900 includes receiving a target EM field value from implantable device 102. The target EM field value is transmitted by implantable device communication device 122 to charger communication device 124. Charger communication device 124 relays the target EM field value to charger controller 106. The target EM field value is determined or estimated by field estimator 132 as described above.

[0072] At block 906, process 900 includes determining whether the wireless charger can generate a charging EM field. The determination made by the charger controller 106 includes whether the wireless charger 104, at its current position on the user's body, can generate a field that would cause or result in a voltage level at or above V. HTarget V H The EM field 108. The charger controller 106 compares the beacon current with a predetermined threshold maximum current that can be generated by the EM field driver 128 to produce the EM field 108, and also V HB With V HTarget This determination is made through comparison. The charger controller 106 determines that when V... HB With V HTarget When the ratio is related to the ratio of beacon current to maximum threshold current, the wireless charger 104 can generate the desired EM field 108. In some cases, other factors, such as scalar multipliers or exponents, can be used in this determination to scale more accurately between the current value and the field strength, which may not increase and / or decrease in a 1:1 ratio.

[0073] At block 908, process 900 generates an alignment notification. If charger controller 106 determines at block 906 that charging EM field 108 is possible in its current position, charger controller 106 generates a notification to the user at block 908 that the implantable device 102 and wireless charger 104 are aligned for charging. Charger controller 106 may relay the notification to a notification device for use in reminding or notifying the user.

[0074] If at block 906, the charger controller 106 determines that the maximum threshold current will not be generated, resulting in V... HTarget If the EM field is not clear, the charger controller 106 can generate a notification to the user to move the wireless charger 104 to find a better alignment. The process 900 can be iterative to help the user align the wireless charger 104 with the implantable device 102 without requiring perfect alignment. The notification to the user regarding the movement of the wireless charger can provide guidance or instruction on the direction of movement, or it can simply instruct the user to move the charger without further information. The guidance or instruction can take the form of a graphical user interface (“GUI”) with arrows or other indicators showing which direction the charger should move. The controller, more specifically the controller’s processor, can determine the direction based on a historical mapping of wireless field data as the charger has been moved by the user. For example, the user might place the charger in a first location to attempt charging, but this location is not within the appropriate position or range for charging. The charger may include a position sensor, such as an optical sensor, a proximity sensor, a gyroscope, GPS, or other suitable sensors known in the art for providing position data. The user can move the charger once or multiple times, and the controller stores data related to the beacon EM field at each location.

[0075] In some examples, a user may attempt to align the wireless charger 104 and the implantable device 102 for a period of time without success. As the user moves the charger in an attempt to align, the charger controller 106 and / or the wireless charger 104 can track various V... HB The location associated with the value. After a predetermined period of time, the wireless charger 104 and / or charger controller 106 may determine to enter a best-effort mode for utilizing the highest V value. HB Charging is performed at the associated location. The charger controller 106 can then generate a notification via the notification device 136, instructing the user to return to the location with the highest V. HB The associated location. In some examples, the charger controller 106 may store or instruct a computing device to store previous field values, such as V. HB .

[0076] In some examples, the notification device 136 may notify the user using tactile, visual, auditory, or any other suitable notification method. For example, the charger controller 106 may instruct the notification device 136 to display an arrow indicating the direction in which the charger is moved to return to the highest V in the aforementioned best-effort mode. HB The associated location. The notification device 136 can provide different tones, frequencies, patterns, or other modulations for the notification based on alignment quality. Alignment quality can be based on V... HTarget and V HB Value. For example, charger controller 106 determines that V can be generated when the current through EM field driver 128 is low. HTarget V HB It may have higher alignment quality, and the notification device 136 may increase the frequency or pitch of the auditory notification based on the higher alignment quality to help the user identify a better alignment position.

[0077] The foregoing description of some examples has been given for illustrative purposes and is not intended to be exhaustive or to limit this disclosure to its exact form. Many modifications and adaptations thereto will be apparent to those skilled in the art without departing from the spirit and scope of this disclosure.

[0078] References to examples or implementations herein are intended to imply that a particular feature, structure, operation, or other characteristic described in connection with that example may be included in at least one implementation of this disclosure. This disclosure is not limited to the particular example or implementation described therein. The use of the phrases “in an example,” “in the example,” “in an implementation,” or “in an implementation,” or variations thereof, in various places throughout the specification, does not necessarily refer to the same example or implementation. Any particular feature, structure, operation, or other characteristic described in this specification with respect to an example or implementation may be combined with other features, structures, operations, or other characteristics described with respect to any other example or implementation.

[0079] This article intends to cover both inclusive and exclusive "or" conditions in its use of the word "or". In other words, A or B or C includes any or all of the following substitutions suitable for a particular purpose: A alone; B alone; C alone; only A and B; only A and C; only B and C; and all three of A, B, and C.

Claims

1. A system for wireless charging, the system comprising: an implantable device comprising: a rectifier circuit; an electromagnetic (EM) field receiving coil to receive a charging EM field, the EM field receiving coil electrically connected to the rectifier circuit; a first antenna; and a processor to iteratively perform a set of operations at a rate based at least in part on power fluctuations at a load, the set of operations comprising: receiving one or more electrical signals from the rectifier circuit and a battery of the implantable device; determining a current EM field value based on the one or more electrical signals, wherein the current EM field value comprises a scalar representing a magnitude of a current EM field at the EM field receiving coil; determining a target EM field value based on the one or more electrical signals; and transmitting, with the first antenna, the current EM field value and the target EM field value; and a wireless charger comprising: a power source electrically connected to a transmitting coil to generate the charging EM field; a second antenna to receive the current EM field value and the target EM field value from the first antenna; and a controller to alter at least one of a voltage or a current of the power source based on the current EM field value and the target EM field value to generate the charging EM field.

2. The system of claim 1, wherein: the processor further determines a battery voltage and a charging current based on the one or more electrical signals; and the processor further determines the target EM field value based on the battery voltage and the charging current.

3. The system of claim 1, wherein, the processor further: determines a rectifier voltage and a rectifier current based on the one or more electrical signals; and determines the current EM field value based on the rectifier current and the rectifier voltage.

4. The system of claim 3, wherein, the processor determines the current EM field value based on an electrical model of the implantable device, the electrical model representing a relationship between the rectifier voltage, the rectifier current, and the current EM field value.

5. The system of claim 4, wherein, the electrical model comprises a table of values corresponding to associated rectifier voltages, rectifier currents, and current EM field values.

6. The system of claim 1, wherein, the controller receives the current EM field value and the target EM field value from the second antenna and increases a current of the power source to increase the current EM field value to approximate the target EM field value.

7. The system of claim 1, wherein: the implantable device further comprises a voltage or current sense circuit connected to the rectifier circuit, the voltage or current sense circuit to sense the one or more electrical signals and transmit the one or more electrical signals to the processor; and the one or more electrical signals comprise at least one of an output voltage or an output current from the rectifier circuit.

8. A method of charging an implantable device, the method comprising iteratively performing a set of operations at a rate based at least in part on power fluctuations at a load, the set of operations comprising: measuring a set of electrical parameters of the implantable device; determining a current electromagnetic (EM) field value at the implantable device based on a first subset of electrical parameters of the set of electrical parameters of the implantable device, wherein the current EM field value comprises a scalar representing a magnitude of a current EM field at an EM field receiving coil; ​ determine a target EM field value at the implantable device based on a second subset of electrical parameters in a set of electrical parameters of the implantable device, the first subset of electrical parameters being different than the second subset of electrical parameters; and send the current EM field value and the target EM field value to a wireless charger for controlling an EM field driver of the wireless charger.

9. The method of claim 8, wherein, The first subset of electrical parameters includes a voltage and a current measured at a rectifier of the implantable device.

10. The method of claim 9, wherein, The current measured at the rectifier includes a sum of one or more currents at the rectifier.

11. The method of claim 8, wherein, The second subset of electrical parameters includes a current battery voltage of a battery of the implantable device and a predetermined charging current for charging the battery.

12. The method of claim 8, wherein, Determining the current EM field value includes comparing the first subset of electrical parameters to an electrical model of the implantable device, the electrical model including a relationship between the current EM field value and the second subset of electrical parameters.

13. The method of claim 12, wherein, The electrical model of the implantable device includes a table of rectifier voltages and rectifier currents and associated current EM field values.

14. The method of claim 8, wherein, Measuring the set of electrical parameters includes receiving one or more signals from at least one of a current sensor or a voltage sensor.

15. A charger system, comprising: a wireless field driver that generates an electromagnetic (EM) field; a signal receiver; and a controller in communication with the wireless charger, the controller comprising: a processor configured to execute processor-executable instructions stored in a non-transitory computer-readable medium, the instructions configured to cause the processor to iteratively perform a set of operations at a rate based at least in part on power fluctuations at a load, the set of operations comprising: receiving a current EM field value from an implantable device, wherein the current EM field value comprises a scalar representing a magnitude of a current EM field at an EM field receiving coil; receiving a target EM field value from the implantable device; determining a power setting for the wireless field driver based on the current EM field value and the target EM field value; and sending the power setting to the signal receiver for controlling a power input to the wireless field driver.

16. The charger system of claim 15, wherein, The target EM field value comprises a target value representing a target EM field strength for charging the implantable device.

17. The charger system of claim 15, wherein, The current EM field value comprises a current estimate value representing a received EM field strength based on an EM field generated by an EM field driver.

18. The charger system of claim 15, further comprising a power conditioning device in communication with the signal receiver and the wireless field driver, the power conditioning device configured to adjust a power source connected to the wireless field driver in response to receiving the power setting.

19. An implantable device, comprising: an EM field receiving coil that receives a charging EM field, the EM field receiving coil electrically connected to a rectifier circuit; a first antenna; and a processor that iteratively performs a set of operations at a rate based at least in part on power fluctuations at a load, the set of operations comprising: receiving one or more electrical signals from the rectifier circuit and a battery of the implantable device; determining a current EM field value based on the one or more electrical signals, wherein the current EM field value comprises a scalar representing a magnitude of a current EM field at an EM field receiving coil; determining a target EM field value based on the one or more electrical signals; and transmitting, with the first antenna, the current EM field value and the target EM field value to a second antenna of a wireless charger.

20. The implantable device of claim 19, wherein: the processor determines a rectifier voltage and a rectifier current based on the one or more electrical signals; and the processor determines the current EM field value based on the rectifier current and the rectifier voltage.

21. The implantable device of claim 20, wherein, the processor determines the current EM field value based on a model of the implantable device, the model representing a relationship between the rectifier voltage, the rectifier current, and the current EM field value.

22. The implantable device of claim 19, wherein: the processor determines a battery voltage and a charging current based on the one or more electrical signals; and the processor determines the target EM field value based on the battery voltage and the charging current.

23. A computer-implemented method comprising: iteratively performing a set of operations at a rate based at least in part on power fluctuations at a load, the set of operations comprising: receiving one or more electrical signals from a rectifier circuit and a battery of an implantable device; determining a current EM field value based on the one or more electrical signals, wherein the current EM field value comprises a scalar representing a magnitude of a current EM field at an EM field receiving coil; determining a target EM field value based on the one or more electrical signals; and transmitting, with a first antenna of the implantable device, the current EM field value and the target EM field value.

24. The computer-implemented method of claim 23, further comprising: determining a battery voltage and a charging current based on the one or more electrical signals; and determining the target EM field value based on the battery voltage and the charging current.

25. The computer-implemented method of claim 23, further comprising: determining a rectifier voltage and a rectifier current based on the one or more electrical signals; and determining the current EM field value based on the rectifier current and the rectifier voltage.

26. The computer-implemented method of claim 25, wherein, determining the current EM field value based on an electrical model of the implantable device, the electrical model representing a relationship between the rectifier voltage, the rectifier current, and the current EM field value.

27. The computer-implemented method of claim 26, wherein, the electrical model comprises a table of values corresponding to associated rectifier voltage, rectifier current, and current EM field value.

28. The computer-implemented method of claim 23, wherein, receiving the current EM field value and the target EM field value from a second antenna of the implantable device and increasing a current of a power source to increase the current EM field value to approximate the target EM field value.

29. The computer-implemented method of claim 23, wherein: the implantable device further comprises a voltage or current sensing circuit connected to the rectifier circuit, the voltage or current sensing circuit sensing the one or more electrical signals and transmitting the one or more electrical signals; and the voltage or current sensing circuit comprises a voltage divider connected to the rectifier circuit, the voltage divider sensing the one or more electrical signals and transmitting the one or more electrical signals. The one or more electrical signals include at least one of an output voltage or an output current from the rectifier circuit.

30. One or more non-transitory computer-readable media comprising computer- executable instructions that, when executed by one or more computing systems, cause the one or more computing systems to: iteratively perform a set of operations at a rate based at least in part on power fluctuations at a load, the set of operations comprising: receive one or more electrical signals from a rectifier circuit and a battery of an implantable device; determine a current EM field value based on the one or more electrical signals, wherein the current EM field value comprises a scalar representing a magnitude of a current EM field at an EM field receiving coil; determine a target EM field value based on the one or more electrical signals; and transmit, with a first antenna of the implantable device, the current EM field value and the target EM field value.

31. The one or more non-transitory computer-readable media of claim 30, further comprising computer-executable instructions that, when executed by one or more computing systems, cause the one or more computing systems to: determine a battery voltage and a charging current based on the one or more electrical signals; and determine the target EM field value based on the battery voltage and the charging current.

32. The one or more non-transitory computer-readable media of claim 31, further comprising computer-executable instructions that, when executed by one or more computing systems, cause the one or more computing systems to: determine a rectifier voltage and a rectifier current based on the one or more electrical signals; and determine the current EM field value based on the rectifier current and the rectifier voltage.

33. The one or more non-transitory computer-readable media of claim 32, wherein, determine the current EM field value based on an electrical model of the implantable device, including using the electrical model representing a relationship between the rectifier voltage, the rectifier current, and the current EM field value.

34. The one or more non-transitory computer-readable media of claim 30, wherein, receive the current EM field value and the target EM field value from a second antenna of the implantable device and increase a current of a power source to increase the current EM field value to approximate the target EM field value.

35. The one or more non-transitory computer-readable media of claim 30, wherein: the implantable device further comprises a voltage or current sensing circuit connected to the rectifier circuit, the voltage or current sensing circuit to sense the one or more electrical signals and transmit the one or more electrical signals; and the one or more electrical signals include at least one of an output voltage or an output current from the rectifier circuit. ​

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