Abstract: Medical device recharging systems include a controller and a separate recharge device that communicate wirelessly together to provide recharging to an implantable medical device. Either the controller or the recharge device may also communicate wirelessly with the implantable medical device to obtain recharge status and other information. There may be multiple recharge devices present within communication range of the controller, and the controller may determine which recharge device to activate depending upon proximity of each recharge device to the implantable medical device. The controller may allow the recharge device that is active at any given time to change so that the patient having the implantable medical device can move about in the area where the recharge devices are located while recharging continues.

Abstract: A transcutaneous energy transfer system, transcutaneous charging system, external power source, external charger and methods of transcutaneous energy transfer and charging for an implantable medical device and an external power source/charger. The implantable medical device has a secondary coil adapted to be inductively energized by an external primary coil at a carrier frequency. The external power source/charger has a primary coil and circuitry capable of inductively energizing the secondary coil by driving the primary coil at a carrier frequency adjusted to the resonant frequency to match a resonant frequency of the tuned inductive charging circuit, to minimize the impedance of the tuned inductive charging circuit or to increase the efficiency of energy transfer.

Abstract: Techniques are disclosed for controlling the transcutaneously transfer of energy to an implantable medical device (IMD) that is in proximity to a conductive object that conducts current in the presence of an electromagnetic field. Various techniques are disclosed for estimating or determining the levels of heat dissipation associated with the object during the transfer of energy. If too much heat is being dissipated, the transfer of energy may be adjusted so that heating remains below acceptable levels.

Abstract: Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue. In one example, a temperature sensor may sense a temperature of a portion of a device, wherein the portion is non-thermally coupled to the temperature sensor. A processor may then control charging of the rechargeable power source based on the sensed temperature.

Abstract: Techniques for transcutaneous transferral of energy to an implantable medical device are disclosed. An embodiment includes a system comprising an implantable medical device having a secondary coil. An external device is provided to transcutaneously transfer energy to the secondary coil. The external device comprises a housing having a side adapted to be positioned in proximity to the secondary coil when the external device is transferring energy to the secondary coil. A temperature sensor is coupled to the side to determine a temperature indicative of heat to which the patient is being exposed during the transfer of energy. A control circuit is adapted to control the transfer of energy to the secondary coil based on the temperature. For instance, the control circuit may limit transfer of energy by controlling times at which transfer of energy occurs or controlling an amplitude of a signal within the external device.

Abstract: External power source, system for controlling and method for predicting heat loss of implantable medical device during inductive recharging by an external primary coil. A primary coil inductively couples energy to a secondary coil when energized and placed in proximity of the secondary coil. Control circuitry, operatively coupled to said primary coil, determines the energy absorbed in said tissue based on a total applied power by said external power source, power lost in said electronic circuitry, power lost in said electronic circuitry, power lost in said primary coil and power applied to said rechargeable power source and controlling said total applied power based upon said energy absorbed in said tissue.

Abstract: Devices, systems, and techniques for controlling charging power based on a cumulative thermal dose to a patient are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. An external charging device may calculate an estimated cumulative thermal dose delivered to the patient during charging over a predetermined period of time. Based on the estimated cumulative thermal dose, the external charging device may select a power level for subsequent charging of the rechargeable power source. In one example, the charging device may select a high power level when the cumulative thermal dose has not exceeded a thermal dose threshold and select a low power level when the cumulative thermal dose has exceeded the thermal dose threshold.

Abstract: System for transcutaneous energy transfer. An implantable medical device, adapted to be implanted in a patient, has componentry for providing a therapeutic output. The implantable medical device has an internal power source and a secondary coil operatively coupled to the internal power source. An external power source, having a primary coil, provides energy to the implantable medical device when the primary coil of the external power source is placed in proximity of the secondary coil of the implantable medical device and thereby generates a current in the internal power source. An alignment indicator reports the alignment as a function of the current generated in the internal power source with a predetermined value associated with an expected alignment between the primary coil and secondary coil.

Abstract: Devices, systems, and techniques for managing heat generated in coils for wireless energy transmission are disclosed. Inductive coupling between two coils (e.g., a primary coil and a secondary coil) may be used to recharge the power source of an implantable medical device. A phase change material may be thermally coupled to the primary coil to absorb heat generated during the inductive coupling and reduce temperature increases of the primary coil. In one example, the phase change material may be configured to absorb heat from an energy transfer coil. A housing may be configured to contain the phase change material and a coupling mechanism may be configured to removably attach the housing to the energy transfer coil.

Abstract: Devices, systems, and techniques for managing heat generated in coils for wireless energy transmission are disclosed. Inductive coupling between two coils may be used to recharge the power source of an implantable medical device. A phase change material may be thermally coupled to a flexible coil to absorb heat generated during the inductive coupling and reduce temperature increases of the flexible coil. The flexible coil may be configured to at least one of transmit energy to or receive energy from a second coil, and the phase change material may be configured to deform with the flexible coil and absorb heat from the flexible coil. The phase change material may be contained within thermally conductive tubes or channels configured in shapes that promote flexibility of the flexible coil.

Abstract: Techniques are disclosed for tuning a frequency at which an external device transcutaneously transfers energy. The transferred energy may be used to charge a rechargeable power source of an implantable medical device (IMD) and/or to power the IMD directly. One embodiment relates to a charging system that may comprise a circuit to drive a primary coil of an external device at a drive frequency and a control circuit to tune the drive frequency based on a characteristic of a monitored signal that is associated with the primary coil. The characteristic is not present when the primary coil is being driven at a resonant frequency of the system. In a specific example, the characteristic comprises a stub pulse and the control circuit is configured to tune the drive frequency based on at least one of a relative timing and a width of the stub pulse.

Abstract: An external device, charge, system and method for an implantable medical device having therapeutic componentry, a secondary coil operatively coupled to the therapeutic componentry and an internal telemetry coil. A primary coil is capable of inductively energizing the secondary coil when externally placed in proximity of the secondary coil. An external telemetry coil is capable of communicating with the internal telemetry coil. Driver circuitry is selectively operatively coupled to the primary coil and to the external telemetry coil. The driver circuitry is switchable between (1) driving the primary coil for inductively energizing the secondary coil and (2) driving the external telemetry coil for communicating with the internal telemetry coil.

Abstract: Far field telemetry operations are conducted between an external device and an implantable medical device while power is being transferred to the implantable medical device for purposes of recharging a battery of the implantable medical device. The far field operations may include exchanging recharge information that has been collected by the implantable medical device which allows the external device to exercise control over the recharge process. The far field operations may include suspending far field telemetry communications for periods of time while power continues to be transferred where suspending far field telemetry communications may include powering down far field telemetry communication circuits of the implantable medical device for periods of time which may conserve energy. The far field operations may further include transferring programming instructions to the implantable medical device.

Abstract: Medical device recharging systems include a controller and a separate recharge device that communicate wirelessly together to provide recharging to an implantable medical device. Either the controller or the recharge device may also communicate wirelessly with the implantable medical device to obtain recharge status and other information. There may be multiple recharge devices present within communication range of the controller, and the controller may determine which recharge device to activate depending upon proximity of each recharge device to the implantable medical device. The controller may allow the recharge device that is active at any given time to change so that the patient having the implantable medical device can move about in the area where the recharge devices are located while recharging continues.

Abstract: An external antenna with a plurality of concentric primary coils recharges an implantable medical device with a secondary coil when the primary coils are placed in proximity of the secondary coil. Selection circuitry determines which of the plurality of concentric primary coils has the most efficient coupling with the secondary coil and drive circuitry drives the selected primary coil with an oscillating current. During a recharge session, selection circuitry periodically checks at least some of the primary coils to determine whether the primary coil with the most efficient connection has changed. An antenna housing may hold the primary coils in a rigid planar relationship with each other or the primary coils may shift with respect to each other, forming a cup-shape around a bulge in the skin created by the implantable medical device.

Abstract: A transcutaneous energy transfer system, transcutaneous charging system, external power source, external charger and methods of transcutaneous energy transfer and charging for an implantable medical device and an external power source/charger. The implantable medical device has a secondary coil adapted to be inductively energized by an external primary coil at a carrier frequency. The external power source/charger has a primary coil and circuitry capable of inductively energizing the secondary coil by driving the primary coil at a carrier frequency adjusted to the resonant frequency to match a resonant frequency of the tuned inductive charging circuit, to minimize the impedance of the tuned inductive charging circuit or to increase the efficiency of energy transfer.

Abstract: A mechanism for transferring energy from an external power source to an implantable medical device is disclosed. An antenna is positioned in proximity of the implantable medical device. The position of a core of the antenna is adjusted relative to the implantable medical device while the antenna is maintained substantially stationary. A frequency of transmission of a power source is adjusted, and the antenna is driven at the adjusted frequency to transfer energy transcutaneously to the implantable medical device. In one embodiment, the frequency of transmission is selected based on an amplitude of a signal in the antenna.

Abstract: A transcutaneous energy transfer system, transcutaneous charging system, external power source, external charger and methods of transcutaneous energy transfer and charging for an implantable medical device and an external power source/charger. The implantable medical device has a secondary coil adapted to be inductively energized by an external primary coil at a carrier frequency. The external power source/charger has a primary coil and circuitry capable of inductively energizing the secondary coil by driving the primary coil at a carrier frequency adjusted to the resonant frequency to match a resonant frequency of the tuned inductive charging circuit, to minimize the impedance of the tuned inductive charging circuit or to increase the efficiency of energy transfer.

Abstract: System for transcutaneous energy transfer. An implantable medical device, adapted to be implanted in a patient, has componentry for providing a therapeutic output. The implantable medical device has an internal power source and a secondary coil operatively coupled to the internal power source. An external power source, having a primary coil, provides energy to the implantable medical device when the primary coil of the external power source is placed in proximity of the secondary coil of the implantable medical device and thereby generates a current in the internal power source. An alignment indicator reports the alignment as a function of the current generated in the internal power source with a predetermined value associated with an expected alignment between the primary coil and secondary coil.

Abstract: A mechanism for transferring energy from an external power source to an implantable medical device is disclosed. An antenna is positioned in proximity of the implantable medical device. The position of a core of the antenna is adjusted relative to the implantable medical device while the antenna is maintained substantially stationary. A frequency of transmission of a power source is adjusted, and the antenna is driven at the adjusted frequency to transfer energy transcutaneously to the implantable medical device. In one embodiment, the frequency of transmission is selected based on an amplitude of a signal in the antenna.