Non-invasive neural activator with adaptive circuitry

Abstract

A topical nerve activation patch includes a flexible substrate, a dermal adherent bottom surface of the substrate including an adhesive and adapted to contact a user's dermis, a flexible top outer surface of the substrate, a plurality of electrodes positioned on the patch proximate the bottom surface and beneath the top outer surface and coupled to the flexible substrate, a power source, and electronic circuitry generating an output voltage applied to the electrodes. The electronic circuitry includes a controller, a voltage monitoring circuit coupled to the controller, a current monitoring circuit coupled to the controller, a switch coupled to the controller, and a two-stage boost circuit coupled to the switch and the power source configured to increase a switch voltage level to approximately half of a final output voltage before increasing to the final output voltage.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 866,845, filed June 26, 2019, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to activating nerves via a local stimulator to control or influence muscles, tissues, organs, or sensations, including pain, in mammals, including humans. Background Technology

[0004] Neurological disorders can lead to loss of control over muscles and other bodily functions, loss of sensation, or pain. Surgical and pharmaceutical treatments sometimes address these conditions, but have limitations. This invention relates to a system for providing additional options for treatment and functional improvement. Attached Figure Description

[0005] Figure 1 The illustration shows a sample patch that is pasted behind a user's ankle bone.

[0006] Figure 2 It is a diagram. Figure 1 A block diagram of a hardware / software related component, serving as an example of a patch.

[0007] Figure 3A This is a circuit diagram of an example of a single-stage boost circuit that provides feedback.

[0008] Figure 3B This is a circuit diagram of an example of a charge application circuit using the output of a boost circuit.

[0009] Figure 3C This is a circuit diagram of an example of a two-stage boost circuit that provides feedback.

[0010] Figure 4 This is a flowchart illustrating the function of a controller that monitors and controls the output voltage (including its ramp rate).

[0011] Figure 5 This is a flowchart of an example based on an adaptive protocol.

[0012] Figure 6 This is based on an example of a differential integrator circuit used in an adaptive protocol.

[0013] Figure 7 This is based on an example table showing charge duration and frequency, used to provide feedback to an adaptive protocol.

[0014] Figure 8The diagram illustrates a charge measurement circuit according to an example invention.

[0015] Figure 9 The illustration shows a stacked view of patches according to the example invention.

[0016] Figure 10A and Figure 10B An example of an electrode according to the invention is illustrated. Detailed Implementation

[0017] Non-invasive neural activators according to various examples disclosed herein include novel circuitry systems to sufficiently boost voltage to the desired level and maintain a substantially constant charge level for neural activation. Furthermore, a feedback loop provides automatic determination and adaptation of the applied charge level.

[0018] Figure 1 The illustration shows an example patch 100, also known as a smart bandage, smart board, local neural activator (“TNA”), or local neural activation patch, which is applied to the area behind the ankle bone 110 of a user 105. Figure 1 In one example, patch 100 is adapted to activate / stimulate the tibial nerve of user 105 and can be specifically shaped to fit the left or right ankle of user 105. In other examples, patch 100 is worn at different locations on user 105 to activate the tibial nerve from different locations or to activate different nerves of user 105.

[0019] Patch 100 is used to stimulate these nerves and is convenient, inconspicuous, self-powered, and controllable via a smartphone or other control device. This offers the advantages of being non-invasive, self-controlled by the consumer, and potentially available over-the-counter without a prescription. Patch 100 provides a means of stimulating nerves without penetrating the dermis and can be applied to the dermal surface at a location suitable for the nerve of interest. In this example, patch 100 is applied by the user and is disposable.

[0020] The patch 100 in the examples can be any type of device that can be securely attached to a user using adhesive in some examples, and includes a processor / controller and instructions executed by the processor, or it can be a hardware implementation without software instructions, and electrodes and associated circuitry for applying electrical stimulation to the user's skin surface. In one example, the patch 100 provides localized nerve activation / stimulation on the user to provide benefits, including bladder management for overactive bladder (“OAB”).

[0021] In one example, patch 100 may include a flexible substrate; a stretchable dermal-adhesive bottom surface of the substrate including an adhesive and adapted to contact dermal skin; a flexible top outer surface of the substrate generally parallel to the bottom surface; one or more electrodes positioned on the patch near the bottom surface and below the top outer surface and in direct contact with the flexible substrate; and an electronic circuit system (as disclosed herein) embedded in the patch and below the top outer surface and as a system-on-a-chip (SoC) directly contacting the flexible substrate, the SoC including the stretchable dermal-adhesive bottom surface configured to electrically activate one or more electrodes. The patch 100 comprises an integrated electrical signal generator, a signal activator coupled to the electrical signal generator, a neurostimulation sensor providing feedback in response to stimulation of one or more nerves, an antenna configured to communicate with a remote activation device, a power supply electrically communicating with the electrical signal generator, and a signal activator configured to activate in response to receiving communication with the activation device via the antenna, and the electrical signal generator configured to generate one or more electrical stimuli in response to activation by the signal activator, wherein the electrical stimuli are configured to stimulate one or more nerves of a user wearing the patch 100 at least at a location near the patch 100. Further details of an example of the patch 100, in addition to the novel details disclosed herein, are disclosed in U.S. Patent No. 10,016,600 entitled “Topical Neurological Stimulation,” the disclosure of which is incorporated herein by reference.

[0022] Figure 2 It is a diagram. Figure 1 A block diagram of hardware / software related components for an example patch 100. Patch 100 includes electronic circuitry or a chip 1000 that performs the following functions: communicating with external control devices such as smartphones or key fobs or external processing devices such as cloud-based processing devices; neural activation via electrodes 1008 that generate a wide-range electric field according to a treatment protocol; and a wide range of sensors 1006, such as, but not limited to, mechanical motion and pressure, temperature, humidity, acoustic, chemical, and positioning sensors. In another example, patch 100 includes a transducer 1014 for sending signals to or receiving signals from tissue.

[0023] One arrangement integrates a wide variety of these functions into a system-on-a-chip 1000. A control unit 1002 is shown for data processing, communication, transducer interface, and storage, along with one or more stimulators 1004 and sensors 1006 connected to electrodes 1008. The control unit 1002 can be implemented by a general-purpose processor / controller, or a dedicated processor / controller or dedicated logic circuitry. An antenna 1010 is incorporated for external communication via the control unit 1002. An internal power supply 1012 is also included, which may be, for example, a battery. Other examples may include an external power supply. More than one chip may be required to accommodate a wide range of voltages for data processing and stimulation. The electronic circuitry and chips will communicate with each other via conductive rails within the device capable of transmitting data and / or power.

[0024] Patch 100 interprets the data stream from control unit 1002 to separate message headers and delimiters from control instructions. In one example, the control instructions include information such as voltage level and pulse pattern. Patch 100 activates stimulator 1004 according to the control instructions to generate a stimulation signal to electrode 1008 placed on the dermis / tissue. In another example, patch 100 activates transducer 1014 to send a signal to the tissue. In yet another example, the control instructions cause information such as voltage level and pulse pattern to be retrieved from a library stored by patch 100 (such as a repository within control unit 1002).

[0025] Patch 100 receives sensory signals from tissue and converts them into a data stream that is recognized by control unit 1002. Sensory signals may include electrical, mechanical, acoustic, optical, and chemical signals. Sensory signals are received by patch 100 via electrodes 1008 or from other inputs originating from mechanical, acoustic, optical, or chemical transducers. For example, an electrical signal from tissue is introduced into patch 100 via electrodes 1008, converted from an analog signal to a digital signal, and then inserted into a data stream transmitted via antenna 1010 to an external control device. In another example, an acoustic signal is received by transducer 1014, converted from an analog signal to a digital signal, and then inserted into a data stream transmitted via antenna 1010 to an external control device. In some examples, sensory signals from tissue are directly interfaced with an external control device for processing.

[0026] In the example of patch 100 disclosed above, when used for therapeutic treatments such as bladder management of OAB, it is necessary to control the voltage by boosting the voltage to a selected level and providing the same level of charge when activating the mammalian nerves. Furthermore, it is necessary to conserve battery life by selectively using battery power. Additionally, it is necessary to create a compact electronic package to facilitate mounting the electronic package, within the size range of a typical band-aid, onto relatively small mammalian skin patches.

[0027] To meet the above requirements, an example implements a novel boost circuit that includes a feedback circuit and a charge application circuit. Figure 3A This is a circuit diagram of an example of a single-pole boost circuit 200 that provides feedback. Figure 3B This is a circuit diagram of an example of a charge application circuit 300 using the output of a boost circuit 200. The boost circuit 200 includes both electronic components and a controller / processor 270, which includes a sequence of instructions that together modify the activation / stimulation voltage level delivered by the patch 100 to the external dermis of the user 105 via electrodes. The controller / processor 270 in this example implements... Figure 2 Control unit 1002.

[0028] Single level V BOOST

[0029] The boost circuit 200 can replace a separate analog-controlled boost regulator by using a digital control loop to create a regulated voltage, output voltage 250, from a battery source. The output voltage 250 is provided as an input voltage to charge the application circuit 300. In this example, this voltage provides a nerve stimulation current through the dermis / skin to provide treatment for overactive bladder. The output voltage 250, or "VB," at the voltage output node 250... oost "Two digital feedback paths 220 and 230 are used via controller 270. In each of these paths, controller 270 uses a sequence of instructions to interpret the measured voltage, or 'V', at voltage monitor 226." ADC "and the quantity measured at current monitor 234 or "I ADC "and determine the appropriate output control for accurate and stable output voltage 250".

[0030] The boost circuit 200 includes an inductor 212, a diode 214, and a capacitor 216 that together implement the boost converter circuit 210. The voltage monitoring circuit 220 includes a top resistor 222 or "R". T ", Bottom resistor 224 or "R" B A resistor divider is formed by voltage monitor 226 and current monitoring circuit 230. Current monitoring circuit 230 includes current measuring resistor 232 or "R". I The circuit includes a current monitor 234. A pulse width modulation ("PWM") circuit 240 includes a field-effect transistor ("FET") switch 242 and a PWM driver 244. An output voltage 250 serves as a sink for electrical energy. An input voltage 260, or "V", is used. BAT It is the source of electrical energy, and can be generated by... Figure 2 This is achieved using a power supply of 1012.

[0031] The PWM circuit 240 alters the "on" time within the fixed-frequency digital square wave signal to change the ratio of the "on" to "off" time of the command power switch. In the boost circuit 200, the PWM driver 244 drives the FET switch 242 to the "on" and "off" states.

[0032] During operation, when FET switch 242 is turned on (i.e., conducted), the drain of FET switch 242 is drained to ground / GND or ground node 270. FET switch 242 remains on until its current reaches a level selected by controller 270, which acts as a servo controller. This current is measured as a representative voltage across current-measuring resistor 232, detected by current monitor 234. Energy is stored in the magnetic field within inductor 212 due to its inductance. Current flows through current-measuring resistor 232 to ground until FET switch 242 is turned on by PWM driver 244.

[0033] When the expected pulse width duration is reached, controller 270 disconnects FET switch 242. Current in inductor 212 is rerouted from FET switch 242 to diode 214, causing diode 214 to relay the current. Diode 214 charges capacitor 216. Therefore, the voltage level at capacitor 216 is controlled by controller 270.

[0034] The output voltage 250 is controlled using an external servo loop comprising voltage monitor 226 and controller 270. The output voltage 250 is measured using a resistive voltage divider with top resistor 222, bottom resistor 224, and voltage monitor 226. The values ​​of top resistor 222 and bottom resistor 224 are selected to maintain the voltage across bottom resistor 224 within the monitoring range of voltage monitor 226. Controller 270 monitors the output value from voltage monitor 226.

[0035] The charge application circuit 300 includes a pulse application circuit 310, which includes an enable switch 314. The controller 270 does not allow the enable switch 314 to be turned on unless the output voltage 250 is within a desired upper and lower range of its desired value. The pulse application circuit 310 is operated by the controller 270 via an assertion enable signal 312, or “VSW,” which turns on the enable switch 314 to allow electrical energy represented by the output voltage 250 to pass through the electrode 320. Simultaneously, the controller 270 continues to monitor the output voltage 250 and controls the PWM driver 244 to turn the FET switch 242 on and off, and maintains the capacitor 216 at the desired value of the output voltage 250.

[0036] The stability of the output voltage 250 can be improved by an optional internal feedback loop via FET switch 242, current measuring resistor 232, and current monitor 234. Controller 270 monitors the output value of current monitor 234 at a faster rate than the monitoring on voltage monitor 226, minimizing voltage variations at the cathode of diode 214, thereby improving control over the voltage swing of output voltage 250 and load sensitivity.

[0037] In one example, a voltage doubler circuit is added to boost circuit 200 to double the high voltage output or reduce the voltage stress on FET 242. When FET 242 is turned on, the voltage doubler circuit accumulates charge in the transfer capacitor and adds voltage to the output of boost circuit 200 when FET 242 is turned off.

[0038] As described, in this example, controller 270 uses multiple feedback loops to adjust the duty cycle of PWM driver 244 to create a stable output voltage 250 across a range of values. Controller 270 uses multiple feedback loops and monitors circuit parameters to control the output voltage 250 and evaluate the appropriate functioning of the hardware. Controller 270 operates according to feedback and monitored values ​​to provide improved patient safety and reduced electrical hazards by disabling erroneous electrical functions.

[0039] In some examples, controller 270 implements monitoring instructions using firmware or software code. In other examples, controller 270 implements monitoring instructions using a hardware state machine.

[0040] In some examples, voltage monitor 226 is an internal feature of controller 270. In other examples, voltage monitor 226 is an external component that transmits its digital output value to the digital input port of controller 270.

[0041] In some examples, the current monitor 234 is an internal feature of the controller 270. In other examples, the current monitor 234 is an external component that transmits its digital output value to the digital input port of the controller 270.

[0042] Compared to known circuits, the boost circuit 200 offers the advantage of reduced component count, leading to lower costs, smaller board size, and higher reliability. Furthermore, the boost circuit 200 provides centralized processing of all feedback data, resulting in faster response to faults. Additionally, the boost circuit 200 controls the input from V... BAT The 260 outflow current increases battery life and reliability.

[0043] Two levels V BOOST

[0044] Figure 3CThis is a circuit diagram of an example of a two-stage boost circuit 280 providing feedback, which can be used as an alternative to circuit 200 in other example inventions. The two-stage boost circuit 280 provides feedback to... Figure 3A The boost circuit 200 is enhanced. The two-stage boost circuit 280 divides the boost circuit 210 of circuit 200 into two parts: the first-stage boost circuit 282 includes an inductor 212, which draws voltage from V... BAT Generate V SWITCH And a first-stage boost circuit 284 including diode D1 214 and capacitor C1 216. Circuit 284 will boost V HALF 288 rose to V BOOST 250.

[0045] The second-stage boost circuit 286 is inserted between circuits 282 and 284 to boost V SWITCH Rise to V HALF In the example invention, V HALF Approximately the final V BOOST Half of the voltage. Circuit 286 includes diodes D2 292 and D3 290, and capacitors C2 293 and C3 291.

[0046] During operation, when FET 242 is "on", V SWITCH The circuit is grounded and the current in inductor L1 212 ramps up. Capacitor C3291 is charged through the forward-biased diode D2 292 to a value greater than V. HALF 288 is approximately one diode voltage drop lower. When FET242 is "turned off," the current in inductor L1 212 is redirected to flow through diode D3 290, thereby charging capacitor C2293. The forward bias on diode D2 292 causes V SWITCH Rise to V HALF Above the voltage. Now, it is charged to V during the previous "on" cycle of FET 242. HALF C3 291 causes the anode side of diode D1 214 to rise to V. HALF Add V SWITCH It is approximately V HALF Twice that, because V SWITCH Approximately V HALF The combined voltage causes diode D1214 to conduct, which in turn charges capacitor C1 to double the voltage.

[0047] and Figure 3A Compared to the circuit 200, the two-stage boost circuit 280 has the advantages of a lower maximum voltage on the FET 242, a lower boost ratio, and a smaller inductor L1 212.

[0048] Figure 4This is a flowchart illustrating the function of the controller 270 that monitors and controls the output voltage 250 (including its ramp rate). In one example, Figure 4 and below Figure 5 The functionality of the flowchart is implemented by software stored in memory or other computer-readable or tangible media and executed by a processor. In other examples, the functionality may be implemented by hardware (e.g., by using an application-specific integrated circuit (“ASIC”), a programmable gate array (“PGA”), a field-programmable gate array (“FPGA”), etc.) or any combination of hardware and software.

[0049] The pulse width modulation of FET switch 242 is controlled by one or more pulses, each pulse width setting allowing more or less charge to accumulate as voltage through diode 214 at capacitor 216. This pulse width setting, referred to as the ramp strength, is initialized at 410. Controller 270 uses a stage index initialized at 412 to sequentially enable each pulse group, one stage at a time, with a predetermined pulse width. The desired ramp strength is converted to a pulse width at 424, which enables and disables FET switch 242 based on the pulse width. During the interval when FET switch 242 is "on", the current is measured by current monitor 234 at 430 and checked against the expected value at 436. When the current reaches the expected value, the stage completes and the stage index is incremented at 440. If the desired number of stages has been applied at 442, the function is complete. Otherwise, the function continues to the next stage at 420.

[0050] because Figure 4 The function of the V used in patch 100 BAT 260 will operate for a longer period because the current drawn from the battery ramps up at a lower rate, thus reducing the peak current required to achieve the final voltage level 250 for each activation / stimulation treatment. The duty cycle of PWM 244 is adjusted by controller 270 to change the ramp strength at 410, thereby improving battery life.

[0051] In known neurostimulation devices, the open-loop protocol used to control the current flowing to the electrodes lacks feedback control. Its commands set the voltage but do not check the actual current delivered. Stimulation pulses are sent based on preset parameters and cannot be modified based on feedback from the patient's anatomy. Electrode placement changes when the device is removed and repositioned. Humidity and temperature of the anatomy also vary throughout the day. If a voltage is preset, all these factors affect the actual charge delivery. Charge control is a crucial feature for patient safety and contributes to improved patient comfort, treatment consistency, and therapeutic efficacy.

[0052] As a contrast, an example of patch 100 includes features that address these drawbacks by using controller 270 to adjust the charge applied by electrode 320. Controller 270 samples the voltage of the stimulation waveform, providing feedback for an adaptive protocol and impedance calculations to modify the stimulation waveform in real time. A differential integrator is used to integrate and sample the current delivered from the stimulation waveform to the anatomical structure, and then summed to determine the actual charge delivered to the user for treatment (such as OAB therapy). After each pulse in a stimulation event, this data is analyzed and used to modify subsequent pulses in real time.

[0053] This hardware adaptation allows the firmware protocol to implement an adaptive protocol. This protocol works by changing the output voltage (“V”). BOOST Electrode 250 is used to adjust the electrical charge applied to the body. The treatment is performed through a series of periodic pulses that deliver the charge into the body via electrode 320. Some treatment parameters are fixed, while others are user-adjustable. Intensity, duration, and frequency can be user-adjustable. Users can adjust these parameters as needed for comfort and effectiveness. If there is discomfort, the intensity can be reduced, and if there is no discomfort, the intensity can be increased. If the maximum acceptable intensity results in ineffective treatment, the duration can be increased.

[0054] Figure 5 The diagram shows a flowchart of an example of the adaptive protocol disclosed above. The adaptive protocol aims to repeatedly and reliably deliver the target charge (“Q”) during treatment. target (and consider any of the following environmental changes:)

[0055] num_pulses←f1(new parameters)

[0056] The number of stimulation pulses during treatment, "num_pulses", is a function of user-provided parameters. Therefore, Figure 5 Its function is to adjust the charge level applied to the user based on feedback, rather than using a constant level.

[0057] Expressed as an update when accumulating a measure of the target charge:

[0058] Qtarget←Qtarget+f2(MON_CURRENT)

[0059] Among them, the accumulated charge "Q" target "This is a function of the monitored current MON_CURRENT. The charge accumulator is fed into the differential integrator output. Therefore, the measured voltage level is proportional to the charge."

[0060] In one example, the adaptive protocol comprises two phases: an acquisition phase 500 and a reproduction phase 520. Any change in user parameters will bring the adaptive protocol to the acquisition phase. When the first treatment begins, a new baseline charge is calculated based on the new parameters. In the new acquisition phase at 502, all data from previous charge applications is discarded. In one example, 502 indicates the first use of the current treatment, where the user places patch 100 on a part of the body and manually adjusts the charge level as a series of charge pulses until it feels appropriate, or changes the charge level manually or automatically at any time. The treatment then begins. The mathematical expression for this charge application function is as follows:

[0061] The charge delivered during treatment is

[0062] Where T is the duration; f is the frequency of the "repetition rate"; Q pulse (i) is the measurement charge delivered by Pulse(i) in the treatment pulse train provided as a voltage MON_CURRENT, which is Figure 6 The result of the differential integrator circuit shown (i.e., the average charge per pulse). Figure 6 The differential integrator circuit 700 is an example of a circuit used to integrate the current measured over time, quantify the delivered charge, and thus determine the charge output on the treatment pulse. The number of pulses in the treatment is T*f.

[0063] like Figure 6 As shown, MON_CURRENT 760 is the result of the differential integrator circuit 700. An analog-to-digital converter (“ADC”) 710 is used to quantize the voltage into a representation of the amount of charge delivered. A Kelvin connection 740 is used to measure the voltage between electrodes A 720 and B 730. Electrodes A 720 and B 730 are connected to a header 750. A reference voltage VREF 770 is included to keep the measurement results within range.

[0064] In some examples, the analog-to-digital converter 710 is an internal feature of the controller 270. In other examples, the analog-to-digital converter 710 is an external component that passes its digital output value to the digital input port on the controller 270.

[0065] At points 504 and 506, each pulse is sampled. In one example, the functions at 504 and 506 are performed for 10 seconds at a pulse rate of 20 Hz, which can be considered a complete treatment cycle. The result of sampling phase 500 is Q. target The target pulse charge.

[0066] Figure 7This is based on an example table showing the number of pulses per treatment measured for two parameters: frequency and duration. Frequency is shown on the Y-axis and duration on the X-axis. Generally, the adaptive protocol performs better with more pulses. One example uses a minimum of 100 pulses to provide reliable convergence for charge data feedback, but fewer pulses can be used in other examples. Reference Figure 7 A frequency setting of 20Hz and a duration of 10 seconds generated 200 pulses, which is desirable for allowing the adaptive current protocol to reproduce previous charges.

[0067] In one example, when the user is in the acquisition phase with a reference charge Q of 500... target Reproducibility phase 520 begins when another follow-up treatment is initiated after the results are collected. For example, as described above, a complete treatment cycle may take 10 seconds. After a two-hour pause, as shown in waiting period 522, the user can then initiate another treatment. During this phase, the adaptive protocol attempts to deliver Q for each follow-up treatment. target The functionality of the reproduction phase 520 is necessary because conditions such as the user's body impedance due to sweat or air humidity may have changed during the waiting period 522. The differential integrator is sampled at the end of each pulse during treatment. At this point, the next treatment begins, and the differential integrator is sampled for each pulse at 524 to correlate with the acquisition phase Q. target Comparisons are made. Pulse sampling includes measuring the pulse output based on the total charge. Figure 6 The voltage output of the integrator (referred to as Mon_Current 760) has a direct linear relationship with the delivered charge and provides a reading of how much charge is leaving the device and entering the user. At 526, each individual pulse is compared with the charge value (i.e., the target charge) determined in the acquisition phase 500, and the next pulse will adjust in the direction of the differential.

[0068] NUM_PULSES=(T*f)

[0069] After each pulse, the observed charge Q pulse (i) Compare with the expected charge for each pulse.

[0070] Q pulse (i)>Q target / NUM_PULSES?

[0071] Then, for subsequent pulses, adjust the output charge or "V" at 528 (decrease) or 530 (increase) using the following formula. BOOST Make the following modifications:

[0072] dV(i)=G[Q target / NUM_PULSES-Q pulse (i)]

[0073] Where G is an empirically determined voltage adjustment factor. The process continues at 532 until the last pulse.

[0074] In some examples, the voltage regulation factor is found in a lookup table stored in the memory of the control unit. In other examples, the voltage regulation factor originates from the logic circuitry within the control unit.

[0075] In some examples, the voltage regulation factor is found in the control unit's software. target NUM_PULSES and Q pulse The value of [i] is sent from the control unit to the external control device in real time, and the value of G is then sent back from the external control device to the control unit in real time.

[0076] Safety features ensure V BOOST It will never be increased by more than 10%. If more charge is needed, the repetition rate or duration can be increased.

[0077] In one example, the boost circuit uses dedicated circuitry to servo the boost voltage. This circuitry processes voltage and / or current measurements to control the PWM duty cycle of the boost circuit's switches. The system controller can set the voltage by adjusting the gain of the feedback loop in the boost circuit. This is accomplished via a digital potentiometer or other analog-to-digital circuitry.

[0078] In one example, generally, during the acquisition phase 500, the current is sampled for each pulse to establish a target charge for reproduction. Then, during the reproduction phase 520, the voltage is adjusted via a digital potentiometer (referred to herein as a “potentiometer (Pot)”) to achieve the established target charge.

[0079] The digital potentiometer is calibrated with the actual voltage upon startup. A table is generated using the sampled voltage for each tap (wiper) value. The table is also pre-calculated to store the potentiometer tap increments required for the 1V and 5V output difference (delta) at each potentiometer level. This allows for rapid reference voltage adjustment during the reproduction phase. Due to battery levels, this table may require periodic recalibration.

[0080] In one example, during acquisition phase 500, the dataset = 100 pulses, and each pulse is sampled, with the average value used as the target_charge for reproduction phase 520. Generally, fewer pulses provide weaker data samples to serve as the basis for reproduction phase 520.

[0081] In one example, during acquisition phase 500, the maximum dataset is 1000 pulses. This maximum value is used to avoid overflow of the 32-bit integer when accumulating the total number of samples. Furthermore, in this example, 1000 pulses is a sufficiently large dataset, and collecting more pulses may not be necessary.

[0082] In the example above, target_charge will be calculated after 1000 pulses. Additional pulses exceeding 1000 during the acquisition phase do not contribute to the calculation of the target charge. In other examples, the maximum dataset exceeds 1000 pulses when longer treatment cycles are desired.

[0083] In one example, the first 3-4 pulses are typically higher than the remaining pulses, therefore these first 3-4 pulses are not used in acquisition phase 500. This is also considered in reproduction phase 520. Using these excessively high values ​​would result in the target charge being set too high and overstimulating subsequent treatments in reproduction phase 520. In other examples, more advanced averaging algorithms can be applied to eliminate high and low values.

[0084] In the example, there might be safety concerns regarding automatically increasing the voltage. For instance, if the connection between the device and the user's skin is poor, the voltage might automatically adjust to its maximum value at 530. Then, for example, the impedance might decrease due to the user pressing the device firmly, potentially causing a sudden surge in current. Therefore, in one example, if the sample is 500mV or higher than the target, it will immediately adjust to the minimum voltage. The example then remains at the reproduction phase 520 and should adjust back to the target current / charge level. In another example, a maximum voltage increase (e.g., 10V) is set for a single treatment. Achieving the established target_charge does not require more than this. In yet another example, a maximum value (e.g., 80V) is set for VBOOST.

[0085] In various examples, stability is desired during the reproduction phase 520. In one example, this is achieved by gradually adjusting the voltage. However, relatively large step sizes can lead to oscillations or overstimulation. Therefore, voltage adjustments can be made in smaller steps. The step size can be based on the difference (delta) between the target current and the sample current, as well as the actual voltage (V). BOOST Voltage level. This facilitates rapid and stable / smooth convergence to the target charge, and allows for more gradual adjustments at lower voltages for more sensitive users.

[0086] The following are conditions that can be evaluated to determine the adjustment step size.

[0087] delta-mon_current = abs(sample_mon_current - target_charge) For increasing the adjustment, if delta_mon_current > 500mV and VBOOST > 20V, then the step size = 5V.

[0088] (For reducing the adjustment, a difference of 500mV will trigger an emergency reduction to the minimum voltage.)

[0089] If delta_mon_current > 200mv, then step size = 1V

[0090] If delta_mon_current > 100mv and delta_mon_current > 5% * sample_mon_current, then step size = 1V

[0091] In other examples, a new treatment begins with a voltage lower than the target voltage, buffered by approximately 10%. The impedance is unknown at the start of treatment. These examples save the target_voltage in use at the end of treatment. If the user does not manually adjust the intensity parameters, a new treatment will begin with the saved target_voltage, buffered by 10%. This quickly achieves the target current with the 10% buffer, thus avoiding potential overstimulation when the impedance is reduced. This also compensates for the typically higher first 3-4 pulses.

[0092] As disclosed, an initial charge level is applied, and then automatically adjusted based on feedback of the applied current amount. The charge amount can vary upward or downward during application. Therefore, instead of setting and then applying a fixed voltage level throughout the treatment cycle, the present invention measures the amount of charge being input to the user and adjusts accordingly throughout the treatment to maintain a target charge level suitable for the current environment.

[0093] The adaptive circuit described above provides a means to monitor the charge transmitted to the user's tissue via electrodes and adjust the intensity and duration of the transmitted charge to adapt to impedance changes through the electrode-skin interface and through the user's tissue, such that the field strength at the target nerve is within the range required to overcome the nerve action potential at that location and activate the nerve impulse. These impedance changes may be due to environmental changes, such as moisture or dryness of the skin or underlying tissue; or due to applied lotion; or due to tissue changes, such as dry skin; or due to changes in the placement of the device on the user's skin, such as due to removing the patch and reapplying the patch at a different location or orientation relative to the target nerve; or due to a combination of the above and other factors.

[0094] The combinational circuitry and circuit control disclosed herein generate a repeatable charge for subsequent use. Voltage boosting conserves battery power by generating voltage on demand. The result is an efficient and compact electronic package suitable for mounting on or within fabric or similar materials to adhere to the dermis, thereby allowing electrodes to be placed near selected nerves to be activated.

[0095] Oscillator timing

[0096] In some examples, controller 270 includes a real-time clock (“RTC”) circuitry for measuring time intervals, including the time between activation pulses and the width of the activation pulses. The RTC circuitry operates continuously on controller 270 to continuously track data in real time. However, this continuous operation consumes power from battery 260.

[0097] In some examples, the RTC circuitry is not used and is set to a non-operating mode by the firmware in controller 270. The firmware uses an on-chip oscillator with a known frequency to set a timer, and thus can measure time intervals. When patch 100 is connected to a key fob or smart controller, the firmware resets the counter to zero, making the zero-time the initial time for subsequent activation events. The firmware adjusts the counter value whenever the time on the timer, as measured by the on-chip oscillator, has elapsed. The firmware can report the counter value to the key fob or smart controller, or both. The key fob and smart controller use their own real-time clock to calculate the real-time value of the activation time by adding a value proportional to the counter value and the activation period to the real-time clock value. This method allows the firmware to avoid using the on-chip real-time clock, thus saving power and extending battery life in patch 100. This method allows the key fob or smart controller to calculate real-time markers for patch 100 activation. These markers are useful for analyzing the operation of patch 100. The on-chip oscillator operates continuously but consumes significantly less power than the on-chip real-time clock.

[0098] Current measurement of charge transfer

[0099] In some examples, the charge delivered to the user is calculated using a differential amplifier, such as... Figure 6 As shown and disclosed above. Figure 8 The diagram illustrates a charge measurement circuit 1100 according to an example invention. Figure 8 The circuit can be used as Figure 6 An alternative to the differential amplifier.

[0100] In circuit 1100, current-measuring resistor 1144 is used to provide controller 270 with a measurement of the current flowing into the load as load current 1120 over time. The amount of charge required to recharge the boost regulator is used as a measurement of the amount of charge transferred to the user at electrode 320. Controller 270 acquires a measured voltage MON_IBAT 1140 proportional to the current input of the boost regulator as an input, and repeats this acquisition for each application pulse. Controller 270 sums the charges calculated from each MON_IBAT 1140 measurement to determine the total charge passing through current-measuring resistor 1144. In a similar manner, controller 270 uses battery voltage-measuring resistor 1132 to measure the voltage VBAT 1110 at battery 260 as MON_VBAT 1130. Controller 270 uses the value of MON_VBAT 1130 to check whether battery 260 continues to output sufficient voltage.

[0101] When with Figure 6 Compared to the differential integrator, Figure 8 The design of Circuit 1100 uses fewer components, does not require precision parts, and uses less space on the printed circuit board.

[0102] Adaptive waveforms for fine intensity control

[0103] The oscillator clock frequency in the example invention is selected to optimize the power consumption of the clock circuit while also providing sufficient speed for microcontroller operation and other timing circuits such as those described above.

[0104] Figure 3A and 3C The PWM circuit modifies the pulse width by changing the count of oscillator clock cycles. Due to the limited clock frequency, it is difficult to achieve sufficient resolution within the PWM duty cycle to create enough different intensity levels in the stimulus. This results in the user being unable to choose between a level that is too weak and the next, higher level that may be too strong.

[0105] Therefore, the example invention includes a control method that, by using the aforementioned level selection via PWM duty cycle and instead enhancing stimulation at the moment the boost voltage ramps up to the desired voltage as read by the microcontroller's analog-to-digital converter (“ADC”), provides greater discrimination between levels. Thus, far more intensity levels are achieved, with smaller gaps between them compared to those limited by PWM resolution based on a much higher ADC measurement frequency. Once the stimulation pulse is delivered to the patient, feedback from the ADC to the microcontroller is used to shorten the PWM activity time.

[0106] In addition to providing more levels of intensity adjustment, the example invention saves battery power by stopping the boost voltage output until the next pulse is needed.

[0107] Furthermore, the PWM duty cycle varies from the first pulse to the last in a series of pulses used for stimulation, using a lower duty cycle pulse at the beginning of stimulation and a higher duty cycle pulse later in the stimulation. The narrower pulses resulting from the lower duty cycle reduce the charging demand on the battery circuitry, allowing the current demand to start more slowly compared to circuits without duty cycle adaptation, and continuing to provide wider pulses and higher current demands through the stimulation pulse sequence to stay within the battery's current specifications while also increasing the stimulation energy to meet the user's needs when adjusting the intensity.

[0108] Lower initial battery current usage allows for improved battery capacity utilization. This optimization allows for more efficient use of the battery charge than circuitry that requires high current delivery when the boost voltage is first enabled.

[0109] Patch stacking

[0110] Figure 9 The illustration shows a stacked view of patch 100 according to an example invention. The substrate 910 is a strip of fabric with adhesive on the skin-facing side. For each electrode 920, a hole 912 is cut out in the substrate. A removable paper 914 is adhered to the adhesive on the skin-facing side of the substrate 910. Two or more electrodes 920 are coupled to a printed circuit board assembly (“PCBA”) 930 via wires 922.

[0111] Electrode 920 is covered with polyimide tape A 924 to prevent short circuits from electrode 920 to PCBA 930 and to prevent electrode 930 from moving within the layers of the assembly. Each electrode 930 has a hydrogel 926 coated on its skin-facing surface. Each electrode 920 has a release layer covering the hydrogel 926. Battery clip 932 is attached to PCBA 930. Battery 936 is inserted into battery clip 932. Battery pull tab 938 is inserted into battery clip 932. PCBA 930 is wrapped in polyimide tape B 934 to restrict user contact with the electronics. Top layer 940 of fabric tape with adhesive on the PCBA-facing side is stacked on top to complete the assembly. Ankle cutout 942 is designed to be shaped like bottom layer 910 and top layer 940 to accommodate the ankle bone and help the user properly position patch 100.

[0112] Hydrogel Adaptive

[0113] Variations in the viscosity and composition of the hydrogel 926 cause the substance to migrate from its original area on each electrode to a wider area, potentially reaching the skin beyond the dimensions of the patch 100. As the hydrogel migrates, its electrical properties change. The circuitry on the PCBA 930 measures the voltage applied to the skin in real time during each treatment. Adaptive circuitry calculates the charge delivered to the skin, a function of many parameters, including the conductivity of the hydrogel 926. Thus, the performance of the patch 100 is maintained, while the hydrogel portion of the device alters its properties. The adaptive circuitry adjusts charge delivery to also account for all variations in body and skin conductivity, sweat, and patch contact.

[0114] As the performance of the hydrogel 926 degrades over time, the adaptive circuitry and firmware in the PCBA 930 record the expected lifespan of a specific patch while it is powered on and on the user's skin. When patch 100 determines that the device's lifespan is nearing its end, the firmware signals a notification to the key fob or smart controller so that the user receives an indication that the patch has reached its limit.

[0115] From electrodes to PCBA crimp connection

[0116] During electrode manufacturing, each electrode 920 is coated with hydrogel 926. In some examples, when manufacturing electrode 920, wires 922 are permanently attached to both the electrode and PCBA 930, such as by soldering. The electrode plus wire plus PCBA assembly is each encapsulated in an airtight bag until they are subsequently assembled with tape and adhesive layers to form a complete patch 100. Due to the complexity of these assembly steps, the hydrogel on the electrode may be exposed to air and moisture for a period of time, which can affect the expected lifespan of the hydrogel.

[0117] In this example, electrode 920 is coated with hydrogel 926, but no wires are attached at this stage. Instead, small clips are soldered to each electrode, which does not affect the hydrogel and avoids attaching the electrodes to any larger components that would require more time on the assembly line. Each of these coated electrodes is individually heat-sealed or otherwise placed in an airtight bag. The hydrogel does not degrade while the coated electrodes are inside the airtight bag.

[0118] In the example, the wire 922 is inserted into a clip previously soldered to the electrode 920. This connection is stronger and less prone to defects compared to directly soldering or attaching the wire harness to the electrode 920. The clip and wire do not affect the hydrogel 926. Each coated electrode 920, along with its clip and attached wire, is placed in an airtight bag using heat sealing or other means. The hydrogel 926 does not degrade while the coated electrode is in the sealed bag. The coated electrodes 920 are removed from their airtight bags only immediately before they are connected to the PCBA 930.

[0119] Another benefit of separating the coating electrode 920 from the PCBA 930 as two distinct sub-assemblies until they are incorporated into the complete patch panel 100 is that defective coating electrodes or those that have expired due to prolonged shelf life can be discarded without the expense of discarding the attached PCBA. The shelf life of the more expensive PCBA is independent of the coating electrode's shelf life. The inventory of these two sub-assemblies can be stored, inspected, and managed independently. This reduces the overall manufacturing cost of the patch panel 100 equipment without compromising its performance.

[0120] Die-cut fabric tape

[0121] In some examples, a solid layer of fabric tape is used to place the bottom layer 910 as the layer above the electrode 920. Therefore, the total thickness of the patch 100 is partly determined by the thickness of the fabric tape above the electrode 920. Furthermore, in order to securely place the electrode 920 on the fabric tape layer, the paper cover on the fabric tape must be pulled back to expose the adhesive coating. This results in a degradation of the adhesive properties of the tape.

[0122] In the example of patch 100, the bottom layer 910 fabric strip is cut to create holes 912 for each electrode 920 according to the defined dimensions of those components. Each electrode 920 is placed in the corresponding hole, without adding thickness to the top of the fabric strip layer. Since it is not necessary to pull back the paper cover to mount the electrode 920 to the fabric strip, the adhesiveness of the fabric strip is unaffected. Holes can be cut with a die to produce precise edges without the possibility of tearing or fibers interfering with the electrode 920.

[0123] Conforms to the contours of the ankle bones

[0124] In some examples, patch 100 has a rectangular shape. This allows the PCBA 930, battery 936, and electrode 920 to be fitted between the fabric and adhesive underlayer 910 and top layer 940, and to be adhered to the skin by the user, then peeled off and discarded after use. In some examples, patch 100 has a shape that conforms to the contour of the location where it will be adhered to the skin. The reference point for correctly positioning patch 100 is the ankle or ankle bone. Therefore, patch 100 has an ankle bone cutout 942 along the vertical side, which accommodates the ankle bone when patch 100 is placed close to it.

[0125] In some examples, the cutout 942 is designed into the patch 100 only on one side, so that the battery 936, PCBA 930, and electrode 920 are properly aligned on either the left or right ankle. Two types of patches 100 can then be provided—one for the left ankle with the cutout 942 on the first vertical side, and another for the right ankle with the cutout 942 on the second vertical side.

[0126] In some examples, cutouts 942 are designed into patch 100 on both vertical sides, allowing the battery 936, PCBA 930, and electrode 920 to be properly aligned on either the left or right ankle. Patch 100 may then be supplied in only one type.

[0127] Battery and battery pull tab

[0128] The patch 100 includes a battery 936, which is surrounded by a battery clip 932 and assembled onto a PCBA 930. During manufacturing, the battery 936 is inserted into the battery clip 932 to secure it and prevent it from falling out. In addition to the battery itself, a battery pull tab 938 is positioned between a contact of the battery 936 and a corresponding contact in the battery clip 932. The battery pull tab 938 prevents the battery 936 and the battery clip 932 from being electrically connected at that contact point until the battery pull tab 938 is removed. When in place, an open circuit exists, preventing the patch 100 from being activated and from consuming power until the battery pull tab 938 is removed.

[0129] In some examples, the battery pull tab 938 is designed to be removed by pulling it out in the opposite direction to the direction in which the battery 936 is inserted into the battery clip 932. This pulling action may cause the battery itself to move because it will be pulled toward the opening side of the battery clip 932. This battery movement may cause the patch 100 to stop operating or never activate.

[0130] In one example, the battery pull tab 938 and battery clip 932 are designed such that the battery pull tab 938 is pulled out in the same direction as the battery 936 is pushed into the battery clip 932. Therefore, the force used to pull the battery pull tab 938 out of the patch 100 is only used to make the battery 936 more secure in its battery clip 932. This reduces the chance of unintentional movement of the battery 936 and its impact on the activation or operation of the patch 100.

[0131] Electrode release film

[0132] Each electrode 920 in the assembled patch 100 is covered with a polyethylene terephthalate (“PET”) silicone-coated release film 926. When the patch 100 is applied to the skin, the release film is pulled off by the user. In some examples, the PET silicone-coated release film 926 is transparent. This can lead to user confusion when the user may not be able to determine whether the tape has been removed. Applying the patch 100 to the skin with any electrode 920 still covered by tape will render the patch 100 ineffective. This ineffectiveness may not be noticeable until the first use of the patch 100. If the applied patch 100 is found to be ineffective when the user experiences urinary urgency, the user may have difficulty urinating properly or removing the patch 100, peeling the tape off the electrodes, or applying a new patch 100 and suppressing the urinary urgency with a re-applied or new device.

[0133] In the example, the PET silicone cover release film 926 covering the electrode 920 is chosen to be a color that is easily visible to the user, making it easy for the user to determine whether the tape has been removed.

[0134] The example uses a circuit system and firmware to stimulate the electrode circuitry with short, low-energy pulses or pulse sequences when patch 100 is initially activated. If patch 100 is activated before being applied to the skin, the electrode readiness test will fail. In this case, the electrode readiness test is repeated repeatedly according to a timer in the firmware or hardware until either all timers expire or the test passes. The test passes when patch 100 exhibits circuitry performance suitable for its design. The test fails when patch 100 is not properly prepared, such as by not removing the electrode film or by not being applied to the skin when all timers expire. When the electrode readiness test fails, patch 100 signals a notification to a key fob or smart controller, which in turn notifies the user. The electrode readiness test is implemented in a way that may be imperceptible to the user and minimizes battery power consumption during testing.

[0135] Removable paper

[0136] In some examples, removable paper 914 covers the adhesive side of the base layer 910. The removable paper 914 can be in multiple sections, each of which is pulled apart by the user when the patch 100 is applied to the skin. These removable papers can supplement the sheet covering the PET film 926 of each electrode 920. Therefore, in the example, the user must remove all these sheets to expose the full adhesive surface for fixation to the skin.

[0137] In the example, the bottom layer 910 is a single sheet with one removable paper 914. The user removes all removable papers in one action. In the example, the bottom layer 910 may be two or more sheets with two or more removable papers 914. The user removes all removable papers. In the example, each removable paper 914 is designed with a pull tab so that the user can pull the removable paper from the bottom layer in a direction perpendicular to the long axis of the patch 100. This movement reduces the forces exerted on the internal components of the assembled patch 100.

[0138] In the example, removable paper 914 covers the substrate 910 and all PET film portions 926. An adhesive attaches the top surface of the removable paper to the skin-facing surface of the polyimide tape A, allowing the user to pull the removable paper from the substrate and remove the PET film from the electrode 920 in one action.

[0139] The patch 100 can also be made more comfortable by adding materials, such as cushioning materials that can buffer electrodes and electronic components, between the top and bottom layers. In at least a portion of the patch 100, the cushioning material may be disposed below the bottom layer and above the top layer. The cushioning material may include cellulose fibers (e.g., wood pulp fibers), other natural fibers, synthetic fibers, woven or nonwoven sheets, loosely woven meshes or other stable structures, superabsorbent materials, foams, adhesive materials, and combinations thereof.

[0140] Hydrogel overlaps with electrode edge

[0141] In some examples, each electrode 920 is covered with hydrogel 926, which conforms to the size of the electrode 920 such that when the patch 100 is applied to the skin, the edge of the electrode 920 is exposed to the user's skin. During the application of the patch 100 to the skin, this edge may abrade or cut the user's skin.

[0142] In some examples, the hydrogel 926 is sized to overlap the edge of the electrode 920. The hydrogel 926 is placed on the electrode 920 with the placement accuracy used in manufacturing, such that the edge of the electrode 920 is always covered by the hydrogel 926. This prevents the edge of the electrode 920 from contacting the user's skin. Therefore, the risk of the electrode 920 abrading or cutting the user's skin is eliminated.

[0143] Safety inspection of switches

[0144] In some examples, as described above, the FET switches in the circuit are turned on and off according to control from the firmware. When neural activation is required, the switch closes to provide voltage to electrode 920. When neural activation stops, the switch is opened to stop providing voltage to electrode 920. In the example, the firmware checks the on or off state of each switch before issuing a command to change the state. Before commanding a switch to close, the firmware checks if the switch is in the on state; and before commanding a switch to open, the firmware checks if the switch is in the closed state. The state is checked by passing a low voltage across the switch, the magnitude of which is sufficient to be detected by the ADC in controller 270, but below the magnitude perceptible to the user's skin.

[0145] In the example, whenever a switch is in the closed state, controller 270 measures the voltage at each switch, and if the measured voltage exceeds a maximum limit, the switch opens and the voltage check fails. These state checks and voltage checks are performed as part of each control routine in the firmware related to changing the switch state. If an error state is detected, the firmware records the error state in the controller's non-volatile memory, disables the voltage circuitry, and places the entire patch 100 into a safe state. This safe state prevents activation, and patch 100 is considered invalid and discarded.

[0146] Matrix pattern in electrodes

[0147] Figure 10A and 10B An example of an electrode according to an exemplary invention is illustrated. Figure 10A In this process, each of the two electrodes 920 is plated onto a substrate layer that forms a continuous region. Figure 10B In this design, each of the two electrodes 920 is electroplated in a matrix pattern, resulting in a flat surface for each electrode 920. There is no waviness that can occur with continuous plating areas, and the electrodes 920 lie flat against the user's skin. Each element of the matrix is ​​connected to a common junction driven by an activation voltage, such that the activation voltage is simultaneously applied to all elements of the matrix.

[0148] calculate Figure 10B The total area of ​​the matrix-formed electrodes 920 is designed to provide sufficient coverage on the user's skin to allow for variations in electrode placement at target locations for neural activation.

[0149] Several examples are illustrated and / or described herein. However, it will be appreciated that the above teachings cover modifications and variations of the disclosed examples without departing from the spirit and intended scope of the invention, and such modifications and variations are within the scope of the appended claims.

Claims

1. A local neural activation patch, comprising: Flexible substrate; The substrate has a genuine leather-bonded bottom surface, which includes an adhesive and is adapted to contact the user's genuine leather. The flexible top outer surface of the substrate is substantially parallel to the bottom surface; Multiple electrodes are positioned on the patch near the bottom surface and below the top outer surface and coupled to the flexible substrate; The power source has a battery voltage level; as well as An electronic circuit system, embedded in the patch and located below the top outer surface and coupled to the flexible substrate, generates an output voltage applied to the electrodes. The electronic circuit system includes: Controller; A voltage monitoring circuit coupled to the controller; A current monitoring circuit coupled to the controller; A switch coupled to the controller; and A two-stage boost circuit is coupled to the switch and the power supply and includes a first stage and a second stage, the second stage being configured to increase the battery voltage level to approximately half the final output voltage, and the first stage being configured to increase the final output voltage to approximately half the final output voltage. The electronic circuit system further includes: A voltage output node coupled to at least one of the electrodes; A grounding node coupled to at least one of the electrodes; The first level includes: An inductor coupled to the power supply and the switch; and A third capacitor coupled to the third diode and the voltage output node; The second level includes: A first capacitor coupled to a first diode and a second capacitor coupled to a second diode, the first capacitor being configured to be charged to approximately half the value of the final output voltage by a diode drop, and the second capacitor being configured to be charged to approximately half the value of the final output voltage.

2. The local neural activation patch of claim 1, wherein the voltage monitoring circuit measures the level of the output voltage and includes a resistive voltage divider.

3. The local neural activation patch of claim 1, wherein the current monitoring circuit measures the level of current applied by the electrodes.

4. The local neural activation patch of claim 1, wherein the switch is configured to be turned on and off to generate a pulse width modulation including an output voltage, and the switch is controlled by the controller.

5. The local neural activation patch of claim 1, wherein when the patch is coupled to a user to generate a treatment, the controller is configured to: Determine the target charge level; A series of pulses are output from the electrode; For each output pulse, the charge value of the pulse is measured and compared with the target charge level; If the charge value is greater than the target charge level, then reduce the intensity level of subsequent output pulses; as well as If the charge value is less than the target charge level, then increase the intensity level of the subsequent output pulse.

6. The local neural activation patch of claim 5, wherein the series of pulses is defined based on frequency and duration.

7. The local neural activation patch of claim 5, wherein the target charge level Q is determined. target This includes generating a series of acquisition pulses and Where T is the duration of the series of acquisition pulses, f is the frequency of the series of acquisition pulses, and Q pulse (i) is the measured charge of each pulse in the series of acquisition pulses.

8. The local neural activation patch of claim 5, wherein the electronic circuitry further comprises a current measuring resistor that provides the controller with a measurement of the current flowing into the load over time.

9. The local neural activation patch of claim 1, wherein the controller is adapted to control the level of the output voltage based on a voltage measurement from the voltage monitoring circuit and a current measurement from the current monitoring circuit.

10. The local neural activation patch of claim 9, wherein the level of the output voltage is controlled by setting one or more pulses of pulse width modulation generated by the switch, and the ramp rate of the control output voltage is set.

11. The local neural activation patch of claim 4, further comprising stimulating the user's nerves via the electrodes when the final output voltage is reached.

12. The local neural activation patch of claim 4, wherein the pulse width modulation includes a duty cycle varying from the first pulse to the last pulse in a series of pulses.

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