Abstract: A neuromodulation system, device, and method are disclosed. In an embodiment, a neuromodulation system includes a processor, a signal generator, a first electrode, and a second electrode. The processor in cooperation with the signal generator, the first electrode, and the second electrode are configured to deliver a transcutaneous stimulation to a mammal. The transcutaneous stimulation is configured by the processor for inducing voluntary movement in the mammal. The first electrode is positioned transcutaneously on a spinal cord and/or spinal cord dorsal roots of the mammal. Additionally, the second electrode is placed transcutaneously on or over at least one of the spinal cord and/or the spinal cord dorsal roots, a muscle, a nerve, or on or near a target end organ or bodily structure of the mammal. The second electrode is in communication with the first electrode through a hardwire or wireless connection.

Abstract: An in-vivo implantable medical device includes a housing, an electronic circuit component, a power reception coil, and a magnetic material. The housing is formed of a biocompatible material and forms an internal space. The electronic circuit component is disposed in the internal space. The power reception coil is disposed in the internal space, interacts with an external electromagnetic field to form an electromagnetic resonance field to receive power. At least part of a region of the housing in which the electromagnetic resonance field is formed is formed of a biocompatible nonmetal material.

Abstract: A method for wirelessly powering a device includes: acoustically coupling an acoustic transmitter to an external surface of a mammal at an approximate location of an implantable device disposed in the mammal; producing, with the acoustic source, acoustic energy having a frequency in a frequency range of about 0.5 MHz to about 3 MHz; receiving the acoustic energy with one or more transducers in the implantable device, the one or more transducers electrically connected to an electric circuit, the one or more transducers having a length in a length range of about 1 wavelength to about 10 wavelengths of the acoustic energy; converting, with the one or more transducers, the acoustic energy to electric energy; and providing the electric energy to a device electrically connected to the electric circuit.

Abstract: A medical apparatus for a patient comprises an external system and an implantable system. The external system is configured to transmit one or more transmission signals, each transmission signal comprising at least power or data. The implantable system is configured to receive the one or more transmission signals from the external system, and to deliver stimulation energy to the patient. Methods of delivering stimulation energy are also provided.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may allocate, for at least a period of time, one or more first antennas for energy harvesting from a transmission. The UE may allocate, for at least the period of time, one or more second antennas for data communication. Numerous other aspects are described.

Abstract: The present disclosure relates to implantable neuromodulation devices, and in particular to a wireless power coil in a low profile environment such as with a neurostimulator. Particularly, aspects of the present disclosure are directed to a medical device that comprises a lossy housing surrounding a power supply, and a receiving coil configured to exchange power wirelessly via a wireless power transfer signal and deliver the power to the power supply. The receiving coil is adjacent the lossy housing. The receiving coil is a helical structure with a total rise that is less than or equal to a height of the lossy housing.

Abstract: The invention relates to a transmitter unit (12) comprising a housing (20), a transmitter coil (18) arranged in the housing (20) for inductively transferring electrical energy to a receiver unit (14) which is provided with a receiver coil (16) and is arranged in the tissue (2) of the body (1) of a patient when the housing (20) having a contact surface (22) is placed on the body (1), and comprising a control device (30) for controlling the operation of the transmitter coil (18). According to the invention, a temperature sensor (26) is provided in the transmitter unit for determining a heating of the tissue (2) of the body (1) caused by the inductive transfer of electrical energy to the receiver unit (14).

Abstract: A three-dimensional part as well as a method and system for creating the three-dimensional part. The three-dimensional part including a first portion of a three-dimensional part formed from a first plurality of successively deposited layers, with a cavity defined in the first portion of the three-dimensional part. A magnet is inserted in the cavity and a cover disposed on the magnet in the cavity. In addition, a second portion of the three-dimensional part is formed form a second plurality of successively deposited layers deposited on the first portion of the three-dimensional part and the cover.

Abstract: A triboelectric generator is disclosed. The triboelectric generator according to an embodiment of the present disclosure includes a flexible electrode part comprising a first and a second dielectric layer, and at least one metal layer; and a fixed electrode part spaced apart from both sides of the flexible electrode part, and comprising a first and a second electrode connected to each other, wherein the flexible electrode part generates triboelectrification based on contact and non-contact by a fluid flow, and an electric charge moves through the metal layer, thereby effectively moving electric charges generated by triboelectrification, and increasing the friction frequency to enhance power generation efficiency.

Abstract: In an implanted medical device system, an internal controller, external power transmitter and methods for regulation of TETS power for an implanted medical device system are disclosed. According to one aspect, a method in an external power transmitter of an implanted medical device system includes determining a current in an external coil of the external power transmitter, multiplying the determined current by a supply voltage to determine a power delivered to the external coil, and controlling the power delivered to the external coil by adjusting the current in the external coil.

Abstract: In an implanted medical device system, an external power transmitter and methods for adjusting a rate of search pulse transmission by an external power transmitter of an implanted medical device system are disclosed. According to one aspect, a method includes detecting a condition of the external power transmitter, and selecting among rates of transmission of search pulses based on the detected condition.

Abstract: An antenna for wireless power transfer includes a first antenna terminal, a second antenna terminal, at least one inner turn, the at least one inner turn having an inner turn width, and at least one outer turn, the at least one outer turn having an outer turn width, the outer turn width greater than the inner turn width. The antenna further includes a substrate positioned underneath the at least one inner turn and the at least one outer turn and a plurality of separate panes of a magnetic shielding material. Each of the plurality of separate panes are positioned substantially co-planar, with respect to each other, and positioned between the substrate and both the at least one inner turns and the at least one outer turns.

Abstract: Described is a locomotive implant for usage within a predetermined magnetic field. In one embodiment magnetohydrodynamics is used to generate thrust with a plurality of electrodes. In another embodiment, asymmetric drag forces are used to generate thrust.

Abstract: The present disclosure provides systems and methods for wirelessly charging an implantable medical device. An external charging device includes a coil, signal generating circuitry to drive current through the coil at a charging frequency to induce current in a second coil in the implantable medical device, monitoring circuitry to generate an output signal to monitor charging operations, and a comb filter. The comb filter is configured to apply filtering to the output signal to remove noise from the output signal, wherein the filtering is applied based on the charging frequency. The external charging device is configured to process the filtered output signal to detect a circuit state of charging circuitry of the implantable medical device during charging operations, and the external charging device is configured to vary the charging frequency based, in part, on detection of the circuit state of the charging circuitry of the implantable medical device.

Abstract: Apparatus for use with a medical implant having a receiving coil. A flexible housing to be placed against skin of a subject includes a flexible transmitting coil and control circuitry for driving a current through the transmitting coil to induce a current in the receiving coil. A sensor coupled to the circuitry determines divergence of a resonance frequency of the transmitting coil when flexed from a nominal resonance frequency of the transmitting coil, occurring in the absence of any forces applied to the transmitting coil. One or more electrical components coupled to the circuitry tune the resonance frequency of the transmitting coil. A switch is coupled to each of the electrical components, the switches including transistors having capacitances that depend on the voltage applied to each switch. The circuitry applies a respective DC voltage to each switch. Other applications are also described.

Abstract: A stimulation system for a patient is provided. The system comprises: at least one implantable device comprising at least one implantable antenna; and an external device comprising at least one external antenna, wherein the at least one external antenna transfers power to the at least one implantable antenna. The at least one implantable device delivers therapy to the patient. A patient attachment device or body covering positions the at least one external antenna relative to the patient.

Abstract: An implantable medical system includes an implantable medical device and a external charger. The implantable medical device includes a rechargeable power source, electronic components coupled to the rechargeable power source to deliver a therapy to or monitor a parameter of a patient, and a recharge system operably coupled to the rechargeable power source including a secondary coil to receive power via an inductive power transfer. The external charger includes a housing forming an internal compartment, recharger electronic components disposed on a printed circuit board assembly in the internal compartment, and a recharge coil assembly disposed within the internal compartment, the recharge coil assembly including a recharge coil to provide power to the secondary coil via the inductive power transfer and a flux guide having a ferrite sheet disposed between the recharge coil and the printed circuit board assembly.

Abstract: Methods and systems are disclosed wherein temperature in a device such as an ambulatory infusion pump is monitored during inductive charging of the device such that temperature-sensitive contents or components, such as, for example, insulin, particular circuitry and/or other components are not damaged. Temperature can be monitored in the device at one or more locations during inductive charging. If the temperature breaches one or more predetermined thresholds and/or is rising at a rate greater than one or more predetermined thresholds, charging can be suspended or provided at reduced power to prevent the temperature from further rising and damaging the contents and/or components of the device. One or more alerts associated with these events may also be triggered so that the user is aware of the situation and may take corrective action.

Abstract: The present disclosure relates to implantable neuromodulation devices, and in particular to a wireless power coil for a neuromodulation device that is to be implanted in a minimally invasive manner, for example, through a trocar or cannula. Particularly, aspects of the present disclosure are directed to a medical device that includes a lossy housing surrounding a power supply, and a receiving coil configured to exchange power wirelessly via a wireless power transfer signal and deliver the power to the power supply. The receiving coil is spaced a predetermined distance from the lossy housing. The medical device further includes a gap provided between the lossy housing and the receiving coil on a vertical plane, and a spacer that fills in at least a portion of the gap to maintain the lossy housing a predetermined distance from the receiving coil.

Abstract: A computer implemented method, system and device are provided. The method transmits an energizing signal from an external antenna, coupled to a local external device (LED), to an implanted antenna of a passive implanted medical device (PIMD). The energizing signal is transmitted while the external antenna is at first and second positions. The method receives, at the external antenna, first and second energy transfer characteristic (ETC) values associated with the first and second positions, respectively. The method is under control of one or more processors configured with program instructions. The method analyzes the first and second ETC values to determine a difference therebetween. The method provides an energy transfer level (ETL) indicator based on the difference between the first and second ETC values. The ETL indicator provides feedback regarding a degree of energy transfer associated with at least one of the first and second positions.

Abstract: A non-pressure continuous blood pressure measuring device, comprises: a radar sensing module, an electro-cardiac sensing module and a microprocessor. The radar sensing module includes at least a transmitter and a receiver, the transmitter continuously provides a pulse wave signal to an artery, the receiver receives a reflected pulse wave signal. The electro-cardiac sensing module includes at least an electrode; the electro-cardiac sensing module receives an electro-cardiac signal through the electrode. The microprocessor is in signal transmittable connection with the radar sensing module and the electro-cardiac sensing module. The microprocessor controls the radar sensing module and the electro-cardiac sensing module, and simultaneously receives the reflected pulse wave signal and the electro-cardiac signal. The microprocessor determines a blood pressure parameter of the artery according to the reflected pulse wave signal and the electrocardiography signal.

Abstract: A method for data exchange and charging is provided. An implantable medical device is monitored and charging of the implantable medical device is initiated by providing charge parameters to a bedside monitor. Communication is initiated between a puck associated with the bedside monitor and implantable medical device. The implantable medical device is charged using the charge parameters. Simultaneously with the charging, transfer of data between the implantable medical device and the bedside monitor is initiated.

Abstract: A sensor includes a radio frequency interrogator, a responsive patch, a radio frequency resonance detector, and a transmission line. The radio frequency interrogator is configured to produce an electromagnetic interrogation pulse having a first frequency. The responsive patch includes a substrate and a resonant layer disposed on a surface of the substrate. The substrate includes a polymer. The resonant layer includes an electrically conductive nanomaterial. The resonant layer is configured to resonate at the first frequency in response to receiving the electromagnetic interrogation pulse. The radio frequency resonance detector is configured to detect a resonating response of the responsive patch. The transmission line couples the responsive patch to the radio frequency resonance detector. The transmission line is configured to transmit the resonating response of the responsive patch to the radio frequency resonance detector.

Abstract: The invention relates to a transmitter unit (12) comprising a housing (20), a transmitter coil (18) arranged in the housing (20) for inductively transferring electrical energy to a receiver unit (14) which is provided with a receiver coil (16) and is arranged in the tissue (2) of the body (1) of a patient when the housing (20) having a contact surface (22) is placed on the body (1), and comprising a control device (30) for controlling the operation of the transmitter coil (18). According to the invention, a temperature sensor (26) is provided in the transmitter unit for determining a heating of the tissue (2) of the body (1) caused by the inductive transfer of electrical energy to the receiver unit (14).

Abstract: A power transmitter for wireless power transfer includes a control and communications unit configured to provide power control signals to control a power level of a power signal configured for transmission to a power receiver and including a pulse width modulation (PWM) signal generator for determining and selecting the operating frequency from the operating frequency range. The power transmitter further includes an inverter circuit configured to receive a direct current (DC) power and convert the input power to a power signal, coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face, and a shielding comprising a ferrite core and defining a cavity, the cavity configured such that the ferrite core substantially surrounds all but the top face of the coil.

Abstract: A wireless charger device is configured to charge an implantable medical device (IMD). A patient controller obtains one or more power parameters from the charger device during charging of the IMD. The patient controller estimates a temperature range of the IMD using the one or more power parameters from the charger device and compares to a heating threshold. The patient controller then determines whether one or more spacers are recommended in response to the comparison. The one or more spacers are removably attached to the wireless charger device and are configured to lay in a position between the wireless charger device and a patient's skin to increase a charging path.

Abstract: An antenna for wireless power transfer includes a first antenna terminal, a second antenna terminal, at least one inner turn, the at least one inner turn having an inner turn width, and at least one outer turn, the at least one outer turn having an outer turn width, the outer turn width greater than the inner turn width. The antenna further includes a substrate positioned underneath the at least one inner turn and the at least one outer turn and a plurality of separate panes of a magnetic shielding material. Each of the plurality of separate panes are positioned substantially co-planar, with respect to each other, and positioned between the substrate and both the at least one inner turns and the at least one outer turns.

Abstract: Described herein are embodiments of a source high-Q resonator, optionally coupled to an energy source, a second high-Q resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. A third high-Q resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. The source resonator and at least one of the second resonator and third resonator may be coupled to transfer electromagnetic energy from said source resonator to said at least one of the second resonator and third resonator.

Abstract: Systems and methods for improved power transmission are disclosed herein. The system can include an implantable neurostimulator for delivering the one or more electrical pulses to a patient's body. The implantable neurostimulator can include a hermetic housing made of a biocompatible material, an energy storage feature for powering the implantable neurostimulator, a receiving coil assembly including an elongate wire winding wound around a first ferritic core, and control circuitry for controlling recharging of the energy storage feature. The system can include a charging device for wirelessly delivering energy to the implantable neurostimulator. The charging device can include a sending coil assembly including a planar wire winding coupled to a surface of a second ferritic core.

Abstract: A control method of a minimum power input applicable to a wireless power transfer system including a power transmission unit and at least one power receiving unit is provided. The power transmission unit is electrically connected with a control voltage signal and an input voltage signal and accordingly generates the minimum power input. The power transmission unit transmits the minimum power input wirelessly through a wireless transmission to the at least one power receiving unit for receiving. By adjusting the input voltage signal, the duty ratio and resonant frequency of the control voltage signal, the present invention ensures an optimal power transmission efficiency of the wireless power transmission system. Moreover, parameters of a charge pump reservoir and gate driving circuit can be further designed in view of the trend feedback of its gate drive waveforms so as to optimize the effect of the proposed invention.

Abstract: A neuromodulation system includes a conductive element, a magnetic field generator, a power module and a computer processor. The conductive element located internal a patient's body. At least a portion of the conductive element is positioned adjacent to a target tissue. The magnetic field generator is positioned external to the patient's body. The magnetic field generator generates a time varying magnetic field for inducing stimulation of the target tissue in combination with the conductive element to produce stimulation that is larger than that which would occur in the absence of the conductive element. The power module supplies power to the magnetic field generator. The computer processor controls the time varying magnetic field provided by the magnetic field generator according to at least one set of stimulation parameters.

Abstract: Implantable leadless cardiac pacing systems and methods for providing substernal pacing using the leadless cardiac pacing systems are described. In one embodiment, an implantable leadless cardiac pacing system includes a housing, a first electrode on the housing, a second electrode on the housing, and a pulse generator within the housing and electrically coupled to the first electrode and the second electrode. The housing is implanted substantially within an anterior mediastinum of a patient and the pulse generator is configured to deliver pacing pulses to a heart of the patient via a therapy vector formed between the first and second electrodes.

Abstract: A watch charging assembly 10 has a coil 22, a membrane 24 and a back plate 12. The coil 22 is configured to pass electric current received at a first or second contact pad 27, 28. The membrane 24 is affixed to the coil 22 forming a membrane and coil assembly 20. The back plate 12 has a pair of conductive inserts 30. Each conductive insert 30 is aligned with and contacts each contact pad 27, 28. The back plate 12 with the coil 22 and membrane 24 form the charging assembly 10. The charging assembly 10 is configured to form a bottom or underside or, alternatively, be attached to a bottom or underside of a rechargeable battery operated wristwatch 100 and when worn, the charging assembly 10 receives electric current from the wearer to charge a rechargeable battery of the wristwatch 100. The coil 22 can be a pancake coil.

Abstract: A computer implemented method, system and device are provided. The method transmits an energizing signal from an external antenna, coupled to a local external device (LED), to an implanted antenna of a passive implanted medical device (PIMD). The energizing signal is transmitted while the external antenna is at first and second positions. The method receives, at the external antenna, first and second energy transfer characteristic (ETC) values associated with the first and second positions, respectively. The method is under control of one or more processors configured with program instructions. The method analyzes the first and second ETC values to determine a difference therebetween. The method provides an energy transfer level (ETL) indicator based on the difference between the first and second ETC values. The ETL indicator provides feedback regarding a degree of energy transfer associated with at least one of the first and second positions.

Abstract: Devices and methods described herein facilitate rapid wireless recharging, while reducing risk of injury, damage, or discomfort caused by heat generated during recharging. The embodiments described herein are useful in a variety of context, including for IoT devices, personal electronics, electric vehicles, and medical devices, among others.

Abstract: A system and method for powering a medical device that includes a fixture configured for periodic patient proximity; external electrical coupling device integrated into the fixture wherein the external electrical coupling device comprises at least one external energy coupler and is configured to detect presence of an electrical medical device implant in a transmission zone of the external electrical coupling device; an electrical medical device implant, wherein the electrical medical device implant comprises at least one implant energy coupler; and wherein the external electrical coupling device is configured to couple to the implantable medical device through a wireless energy transmission between the external energy coupler and the implant energy coupler when presence of the implantable medical device is within a transmission zone.

Abstract: A charging system for an Implantable Medical Device (IMD) is disclosed having a charging coil and one or more sense coils preferably housed in a charging coil assembly coupled to an electronics module by a cable. The charging coil is preferably a wire winding, while the sense coils are preferably formed in one or more traces of a circuit board. One or more voltages induced on the one or more sense coils can be used to determine one or more parameters (magnitude, phase angle, resonant frequency) indicative of the position between the charging coil and the IMD, which position may include the radial offset and possibly also the depth of the charging coil relative to the IMD. Knowing the position, the power of the magnetic field produced by the charging coil can be adjusted to compensate for the position.

Abstract: Described herein are methods of making and using and apparatus for wirelessly communicating data and providing power, particularly from a location exterior to a body and to an implantable device disposed within a body with tissue. The described embodiments provide apparatus and methods for efficiently transfer data and power between an external transceiver and an (implanted) biomedical device. The method is to modulate power carrier, which wirelessly powers the device, using an asynchronous modulation scheme, such as amplitude shift keying (ASK) modulation, with minimal modulation depth in order to not disrupt the power flow. The digital data is encoded in the pulse width, eliminating the need for synchronization to the power carrier signal and further minimizing the power consumption necessary for data transfer. Additionally, a reverse backscatter method for obtaining data from the implant is described that has flexible, low power operation.

Abstract: A contactless motor vehicle-charging device which, as components, includes a primary side and a secondary side, between which, via at least one air gap, energy can be transferred via inductive and/or capacitive coupling, and each of the components in each case includes at least a portion of a control circuit of the contactless motor vehicle-charging device, wherein at least one of the components includes a field controller and at least one of the components comprises a field measurement device which is designed to acquire a magnetic and/or electric field strength, wherein the field controller is designed to use in at least one control operation the acquired field strength as an actual value and, by this actual value and a predetermined setpoint value, to set at least one field strength of the contactless motor vehicle-charging device as a control variable.

Abstract: A method and system for gastric stimulation and imaging for a user. The system having an array of millimeter-sized gastric seeds implanted in a stomach area of a user. Each gastric seed is ultrasonically powered and communicates using a transducer, and the transducer has a recorder to measure a bioelectrical activity in the stomach area of the user. A wearable unit (WU) is worn or carried by the user, and the WU wirelessly powers the gastric seeds. The WU wirelessly communicates with the gastric seeds, and the gastric seeds communicate a parameter to the WU based on the bioelectrical activity. Received pulses by the seeds can be used to localize the position of the seeds and guide the wireless power/data transmission in a self-image-guided manner. A processing unit (PU) wirelessly communicates with the WU, and the WU communicates the parameters from the gastric seeds to the PU.

Abstract: An integrated circuit, such as included as a portion of a sensor node, can include a regulator circuit having an input coupleable to an energy harvesting transducer. The integrated circuit can include a wireless receiver circuit coupled to the regulator circuit and configured to wirelessly receive at least enough operating energy to establish operation of the sensor node without requiring the energy harvesting transducer. The integrated circuit can include a digital processor circuit coupled to the regulator circuit and a power management processor circuit. The digital processor circuit or one or more other circuits can include a subthreshold operational mode established by the power management processor circuit based on the selected energy consumption level. For example, establishing the subthreshold operational mode can include adjusting or selecting a supply voltage so as to establish subthreshold operation of a field effect transistor (FET) in the digital processor circuit or other circuits.

Abstract: An electronic device configured to transmit or receive power by inductive power transfer is disclosed. The electronic device includes an inductive charging receiver to receive electromagnetic power through a surface from a magnetic field at an operating frequency within a frequency range of 100 kHz to 1 MHz from an inductive charger. The inductive charging receiver includes a substantially planar inductive coil with a metallic spiral-shaped conductor, and further includes an electrically conductive shield positioned between the conductor of the inductive coil and the surface of the electronic device such that the shield covers the metallic spiral-shaped conductor. The shield may include a metal layer that has a metal thickness in a range of 1 to 70 micrometers, or the shield may be non-metallic. Transmission of electromagnetic power through the shield is allowed in the frequency range for inductive power transfer.

Abstract: The present disclosure relates to implantable neuromodulation devices, and in particular to a wireless power coil for a neuromodulation device that is to be implanted in a minimally invasive manner, for example, through a trocar or cannula. Particularly, aspects of the present disclosure are directed to a medical device that includes a lossy housing surrounding a power supply, and a receiving coil configured to exchange power wirelessly via a wireless power transfer signal and deliver the power to the power supply. The receiving coil is spaced a predetermined distance from the lossy housing. The medical device further includes a gap provided between the lossy housing and the receiving coil on a vertical plane, and a spacer that fills in at least a portion of the gap to maintain the lossy housing a predetermined distance from the receiving coil.

Abstract: A mechanism for transferring energy from an external power source to an implantable medical device is disclosed. A sensor may be used to measure a parameter that correlates to a temperature of the system that occurs during the transcutaneous coupling of energy. For example, the sensor may measure temperature of a surface of an antenna of the external power source. The measured parameter may then be compared to a programmable limit. A control circuit such as may be provided by the external power source may then control the temperature based on the comparison. The programmable limit may be, for example, under software control so that the temperature occurring during transcutaneous coupling of energy may be modified to fit then-current circumstances.

Abstract: A hybrid battery system is provided for extending the shelf-life of rechargeable batteries. The hybrid battery system may contain sets of non-rechargeable and rechargeable batteries respectively. As the rechargeable batteries are discharged (e.g., from self-discharge), the hybrid battery system may utilize the non-rechargeable batteries to maintain the rechargeable batteries at a preferred state of charge. A preferred state of charge may be selected to extend the shelf-life of the rechargeable batteries. Alternatively, a signal may change the preferred state of charge to prepare the rechargeable batteries for use or for other reasons. The hybrid battery system may contain modular components, thereby allowing for easy replacement of defective or otherwise unsuitable non-rechargeable batteries, rechargeable batteries, or supporting electronics.

Abstract: A device housing for an IMD is suggested, the device housing having: a front side, a flat end face that is arranged perpendicular to the front side and connects to a straight upper edge of the front side, the front side having a maximum width (Bmax) that is measured parallel to the straight upper edge, and a maximum height (Hmax) that is measured perpendicular to the straight edge, wherein the ratio R of maximum width (Bmax) to maximum height (Hmax), i.e., Bmax/Hmax, is between 1.05 and 1.35.

Abstract: An example method includes receiving, by an implantable device and from an external device, an energy signal; transducing, by the implantable device, the energy signal into electrical power; outputting, by the implantable device and to the external device, a feedback signal that represents an absolute level of the electrical power transduced from the energy signal, wherein the feedback signal includes a first portion that represents a relative level of the electrical power transduced from the energy signal and a second portion that represents a reference voltage level; and delivering, by the implantable device, a level of electrical stimulation therapy proportional to the absolute level of the electrical power transduced from the energy signal.

Abstract: A power transmitter for wireless power transfer includes a control and communications unit configured to provide power control signals to control a power level of a power signal configured for transmission to a power receiver and including a pulse width modulation (PWM) signal generator for determining and selecting the operating frequency from the operating frequency range. The power transmitter further includes an inverter circuit configured to receive a direct current (DC) power and convert the input power to a power signal, coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face, and a shielding comprising a ferrite core and defining a cavity, the cavity configured such that the ferrite core substantially surrounds all but the top face of the coil.

Abstract: A portable electronic device includes a battery, a transcutaneous electrical nerve stimulation (TENS) circuit, a power management circuit, a first output unit, and a second output unit. The TENS circuit provides a TENS electrical current. The power management circuit is coupled to the battery and the TENS circuit for managing a power distribution of the portable electronic device. The first output unit receives the TENS electrical current from the TENS circuit and outputs the TENS electrical current to a user. The second output unit receives a power signal from the battery and outputs the power signal to an external electronic device.

Abstract: Apparatus is provided for use with a medical implant having a receiving coil. A flexible housing to be placed against skin of a subject includes a flexible transmitting coil and control circuitry for driving a current through the transmitting coil to induce a current in the receiving coil. A sensor coupled to the circuitry determines divergence of a resonance frequency of the transmitting coil when flexed from a nominal resonance frequency of the transmitting coil, occurring in the absence of any forces applied to the transmitting coil. One or more electrical components coupled to the circuitry tune the resonance frequency of the transmitting coil. A switch is coupled to each of the electrical components, the switches including transistors having capacitances that depend on the voltage applied to each switch. The circuitry applies a voltage of 30-300 volts to each switch. Other applications are also described.