Abstract: An implantable device, such as an infuser device for bidirectional hydraulically controlling a medical artificial sphincter, enhances power transfer characteristics to a secondary coil thereby allowing implantation to greater physical depths and/or enclosing the secondary coil within a housing of the infuser device. The enhanced power transfer is achieved with multiple coils that are longitudinally aligned and physical and electrical parallel to form the secondary loop of a transcutaneous energy transfer system (TET) instead of a single coil. It better optimizes the power transfer from a parallel tuned tank circuit primary coil to an implanted secondary series tuned tank circuit coil.

Abstract: An implantable medical device, such as an implantable pulse generator (IPG) used with a spinal cord stimulation (SCS) system, includes a rechargeable lithium-ion battery having an anode electrode with a substrate made substantially from titanium. Such battery construction allows the rechargeable battery to be discharged down to zero volts without damage to the battery. The implantable medical device includes battery charging and protection circuitry that controls the charging of the battery so as to assure its reliable and safe operation. A multi-rate charge algorithm is employed that minimizes charging time while ensuring the battery cell is safely charged. Fast charging occurs at safer lower battery voltages (e.g., battery voltage above about 2.5 V), and slower charging occurs when the battery nears full charge higher battery voltages (e.g., above about 4.0 V). When potentially less-than-safe very low voltages are encountered (e.g., less than 2.

Abstract: An implantable medical device, such as an implantable pulse generator (IPG) used with a spinal cord stimulation (SCS) system, includes a rechargeable lithiumion battery having an anode electrode with a substrate made substantially from titanium. Such battery construction allows the rechargeable battery to be discharged down to zero volts without damage to the battery. The implantable medical device includes battery charging and protection circuitry that controls the charging of the battery so as to assure its reliable and safe operation. A multi-rate charge algorithm is employed that minimizes charging time while ensuring the battery cell is safely charged. Fast charging occurs at safer lower battery voltages (e.g., battery voltage above about 2.5 V), and slower charging occurs when the battery nears full charge higher battery voltages (e.g., above about 4.0 V). When potentially less-than-safe very low voltages are encountered (e.g., less than 2.

Abstract: A system and method for detecting the status of a rechargeable battery included within an implantable medical device. The medical device can incorporate a status indicator which signals the user concerning the battery status, e.g., low battery level. The signal may be audible or it may arise from an electrical stimulation that is perceptually distinguished from the operative, therapeutic stimulation. The external programmer may also incorporate a second battery status indicator that is visual, audible, or physically felt. Battery status data may be conveyed on visual displays on the external programmer by uploading this information from the medical device using a bi-directional telemetry link. Such battery status data are helpful to the user to indicate when the battery should be recharged and to the clinician to monitor patient compliance and to determine end-of-useful life of the rechargeable battery.

Abstract: A full-body charger for charging one or more battery-powered devices wherein such devices are configured for implanting beneath a patient's skin for the purpose of tissue, e.g., nerve or muscle, stimulation and/or parameter monitoring and/or data communication. Devices in accordance with the invention include a support structure, typically chair-shaped or bed-shaped, capable of supporting a patient's body while providing a magnetic field to one or more of the implanted devices using one or more coils mounted within for providing power to the implanted devices. Consequently, in a preferred embodiment, a single, generally sequential, charging cycle can charge all of the implanted devices and thus minimize the charge time requirements for a patient and accordingly improve the patient's life style.

Abstract: An external transmitter circuit drives an implantable neural stimulator having an implanted coil from a primary coil driven by a power amplifier. For efficient power consumption, the transmitter output circuit (which includes the primary coil driven by the power amplifier inductively coupled with the implanted coil) operates as a tuned resonant circuit. When operating as a tuned resonant circuit, it is difficult to modulate the carrier signal with data having sharp rise and fall times without using a high power modulation amplifier. Sharp rise and fall times are needed in order to ensure reliable data transmission. To overcome this difficulty, the present invention includes an output switch that selectively inserts a resistor in the transmitter output coil circuit in order to de-tune the resonant circuit only during those times when data modulation is needed. Such de-tuning allows sharp rise and fall times in the data modulation without the need for using a high power modulation amplifier.

Abstract: An in-body power supply for supplying energy to an in-body device. The in-body power supply is configured to transfer energy to the in-body device and to compensate for variations and to receive energy without communication between the in-body power supply and an external power source outside the body.

Abstract: Methods and apparatus for providing a sufficiently stable power to a load in an energy transfer system that transfers energy from one side of a physical boundary to another side of he boundary. In one example, a power supply and a primary winding are located on a first side of a physical boundary (e.g., external to a body), and a secondary winding and the load are located on a second side of the physical boundary (e.g., internal to the body). A primary voltage across the primary winding is regulated so as to provide a sufficiently stable output power to the load notwithstanding changes in the load and/or changes in a relative position of the primary winding and the secondary winding. One aspect of the invention relates to energy transfer methods and apparatus for use in connection with the human body. In particular, one example of the invention includes a transcutaneous energy transfer (TET) system for transferring power from a power supply external to the body to a device implanted in the body.

Abstract: A cardiac pacemaker includes a power transmitter which periodically transmits a pulse of a radio frequency signal to a vascular electrode-stent that is implanted in a vein or artery of an animal. The vascular electrode-stent employs energy from the radio frequency signal to charge a storage device which serves as an electrical power supply. The vascular electrode-stent also detects a cardiac signal emitted from the sinus node of the heart and responds thereto by applying a pulse of voltage from the storage device to a pair of electrodes implanted in the vascular system of the animal. Application of the voltage pulse to the electrodes stimulates contraction of the heart.

Abstract: A subcutaneously implantable power supply is a device for powering implantable medical devices. The device has one or more thin photovoltaic cells contained in a case formed of a lamination of a plurality of thin plastic layers. Each layer is translucent in the area covering said cell, such that the power supply is sufficiently flexible to conform to body contours. The device is lightweight, flexible, has improved sealability, and has improved internal battery longevity.

Abstract: A cardiac defibrillator includes a fibrillation detector, which determines when a medical patient requires defibrillation at which time a transmitter produces a radio frequency signal. A first stent electrode is implanted into a blood vessel at a first location in the medical patient and a second stent electrode is implanted into a blood vessel at a second location. The first stent electrode contains an electronic circuit that is electrically connected to the second stent electrode. In response to receiving the radio frequency signal, the electronic circuit uses energy from that signal to apply an electric defibrillation pulse between the first and second stent electrodes.

Abstract: A combination, voltage converter circuit for use within an implantable device, such as a microstimulator, uses a coil, instead of capacitors, to provide a voltage step up and step down conversion functions. The output voltage is controlled, or adjusted, through duty-cycle modulation. In accordance with one aspect of the invention, applicable to implantable devices having an existing RF coil through which primary or charging power is provided, the existing RF coil is used in a time-multiplexing scheme to provide both the receipt of the RF signal and the voltage conversion function. This minimizes the number of components needed within the device, and thus allows the device to be packaged in a smaller housing or frees up additional space within an existing housing for other circuit components. In accordance with another aspect of the invention, the voltage up/down converter circuit is controlled by a pulse width modulation (PWM) low power control circuit.

Abstract: A rechargeable implantable medical device with a magnetic shield placed on the distal side of a secondary recharging coil to improve recharging efficiency is disclosed. The rechargeable implantable medical device can be a wide variety of medical devices such as neuro stimulators, drug delivery pumps, pacemakers, defibrillators, diagnostic recorders, and cochlear implants. The implantable medical device has a secondary recharging coil carried over a magnetic shield and coupled to electronics and a rechargeable power source carried inside the housing. The electronics are configured to perform a medical therapy. Additionally a method for enhancing electromagnetic coupling during recharging of an implantable medical device is disclosed, and a method for reducing temperature rise during recharging of an implantable medical device is disclosed.

Abstract: A rechargeable implantable medical device with an external recharging coil carried on the medical device proximal face is disclosed. The recharging coil can be attached to the medical device housing physically, or chemically, or a combination of both physically and chemically. The recharging coil electrically couples through housing electrical feedthroughs to electronics configured to perform a therapy and a rechargeable power source both carried inside the medical device housing. Additionally methods for attaching the external recharging coil to an implantable medical device are disclosed. The rechargeable implantable medical device can be a medical devices such as a neuro stimulators, drug delivery pumps, pacemakers, defibrillators, diagnostic recorders, cochlear implants, and the like.

Abstract: Disclosed is a medically implantable integrated biocompatible power module incorporating a power source (e.g., battery), a power management circuit (PMC), a magnetically inductive coupling system (MICS) for remote communication and/or inductive charging and a homing device for locating the implanted inductive charging coil. Three configurations are disclosed, each generally suitable for a specified range of energy capacities. The implantable power module (IPM) allows for improved design flexibility for medical devices since the power source may be located remotely and be recharged safely in situ. Special safety aspects may be incorporated, including endothermic phase change heat absorption material (HAM), emergency energy disconnect and emergency energy drain circuits. Communication (one or two way) may be carried out using the inductive charging link, a separate inductive pathway, or other pathway such as RF or via light waves.

Abstract: An implantable electrode, where the electrode comprises a first piezoelectric element which converts mechanical energy into electrical energy, and a cathode and an anode, where electrical energy generated by the first piezoelectric element causes a pacing level energy pulse to be delivered between the anode and the cathode. The mechanical energy for stimulating the piezoelectric element originates from a source external to the implantable electrode. In one embodiment, the external source is from a transmitter that is located on, or integrated into, either a cardiac lead and/or the implantable pulse generator. The electrode further includes an implantable housing into which is integrated the first piezoelectric element and on which is mounted the anode and the cathode. The housing also contains pacing control circuitry, which is coupled to the first piezoelectric element, the anode and the cathode.

Abstract: An implantable medical device, such as an implantable pulse generator (IPG) used with a spinal cord stimulation (SCS) system, includes a rechargeable lithiumion battery having an anode electrode with a substrate made substantially from titanium. Such battery construction allows the rechargeable battery to be discharged down to zero volts without damage to the battery. The implantable medical device includes battery charging and protection circuitry that controls the charging of the battery so as to assure its reliable and safe operation. A multi-rate charge algorithm is employed that minimizes charging time while ensuring the battery cell is safely charged. Fast charging occurs at safer lower battery voltages (e.g., battery voltage above about 2.5 V), and slower charging occurs when the battery nears full charge higher battery voltages (e.g., above about 4.0 V). When potentially less-than-safe very low voltages are encountered (e.g., less than 2.

Abstract: A miniature implantable light source for providing light to an internal treatment site to effect a photodynamic therapy at the site, the light source is powered and/or controlled via acoustic energy transmitted from outside the body to an acoustic transducer in the light source.

Abstract: A cardiac defibrillator for discharging an electrical charge into a patient includes a device for storing mechanical energy, a generator, a capacitor, a charging circuit, a patient interface, an input device, and a control unit. The generator converts mechanical energy stored in the mechanical energy storage device into electrical energy. The charging circuit transfers the electrical energy to the capacitor, wherein the electrical energy is stored in the capacitor. The patient interface provides an electrical path for discharging the electrical energy stored in the capacitor into the patient. The input device is configured to generate a discharge signal. The control unit controls the discharge of the electrical energy into the patient in response to the discharge signal. The mechanical-to-electrical energy converter assembly can also be used to power other medical devices that conventionally run on batteries or AC power line sources.

Abstract: An implantable medical device, such as an implantable pulse generator (IPG) used with a spinal cord stimulation (SCS) system, includes a rechargeable lithium-ion battery having an anode electrode with a substrate made substantially from titanium. Such battery construction allows the rechargeable battery to be discharged down to zero volts without damage to the battery. The implantable medical device includes battery charging and protection circuitry that controls the charging of the battery so as to assure its reliable and safe operation. A multi-rate charge algorithm is employed that minimizes charging time while ensuring the battery cell is safely charged. Fast charging occurs at safer lower battery voltages (e.g., battery voltage above about 2.5 V), and slower charging occurs when the battery nears full charge higher battery voltages (e.g., above about 4.0 V). When potentially less-than-safe very low voltages are encountered (e.g., less than 2.

Abstract: A spiral shield for an implantable secondary coil confines the electrical field of the coil, and thus prevents capacitive coupling of the coil through surrounding dielectrics (such as human tissue.) Known implantable devices receive power inductively, through a secondary coil, from a primary coil in an external device. Efficient power reception requires that the coils be tuned to the same resonant frequency. Use of the spiral shield results in predictable electrical behavior of the secondary coil and permits the secondary coil to be accurately tuned to the same resonate frequency as the primary coil. To further improve performance, spacers made from SILBIONE®LSR 70 reside between turns of the coil to reduce turn to turn and turn to shield capacitances. Reducing the capacitances prevents excessive reduction of the self resonant frequency of the coil. The coil is imbedded in SILBIONE®LSR 70, allowing for a thin and flexible coil.

Abstract: The invention provides a transcutaneous energy transfer device having an external primary coil and an implanted secondary coil inductively coupled to the primary coil, electronic components subcutaneously mounted within the secondary coil and a mechanism which reduces inductive heating of such components by the magnetic field of the secondary coil. For one embodiment of the invention, the mechanism for reducing inductive heating includes a cage formed of a high magnetic permeability material in which the electronic components are mounted, which cage guides the flux around the components to prevent heating thereof. For an alternative embodiment of the invention, a secondary coil has an outer winding and either a counter-wound inner winding or an inner winding in the magnetic field of the outer winding. For either arrangement of the inner coil, the inner coil generates a magnetic field substantially canceling the magnetic field of the outer coil in the area in which the electronic components are mounted.

Abstract: A method to modify a skin surface or a soft tissue structure underlying the skin surface includes a template with a mechanical force application surface and a receiving opening to receive a body structure. The mechanical force application surface is configured to receive the body structure and apply pressure to the soft tissue structure. An energy delivery device is coupled to the template. The energy delivery device is configured to deliver sufficient energy to the template to form a template energy delivery surface.

Abstract: An apparatus and method that will allow for external communication, via an external programmer, for positive device identification and for retrieval of device or patient information stored by an implantable medical device with a depleted power source. The external programmer will deliver energy to a secondary power source located inside the implanted device using RF telemetry sufficient to charge up the secondary power source, e.g., a small capacitor. The capacitor will charge up immediately within milliseconds. Once the secondary power source is sufficiently charged, it can be used to power up a controller having the stored information in the implantable medical device. Once the controller is operational, the implanted device will transmit device and patient information to the external programmer via RF telemetry.

Abstract: Methods and apparatus for providing a sufficiently stable power to a load in an energy transfer system that transfers energy from one side of a physical boundary to another side of he boundary. In one example, a power supply and a primary winding are located on a first side of a physical boundary (e.g., external to a body), and a secondary winding and the load are located on a second side of the physical boundary (e.g., internal to the body). A primary voltage across the primary winding is regulated so as to provide a sufficiently stable output power to the load notwithstanding changes in the load and/or changes in a relative position of the primary winding and the secondary winding. One aspect of the invention relates to energy transfer methods and apparatus for use in connection with the human body. In particular, one example of the invention includes a transcutaneous energy transfer (TET) system for transferring power from a power supply external to the body to a device implanted in the body.

Abstract: A cardiac pacing apparatus has a source of pacing pulses that are transmitted through the animal by a radio frequency signal. An electrode-stent is implanted in a blood vessel adjacent to the point at which stimulation is desired. The electrode-stent contains an electrical circuit that is tuned to the radio frequency signal and which responds to receipt of that signal by applying an electric current to tissue of the animal.

Abstract: Methods and apparatus for providing a sufficiently stable power to a load in an energy transfer system that transfers energy from one side of a physical boundary to another side of the boundary. In one example, a power supply and a primary winding are located on a first side of a physical boundary (e.g., external to a body), and a secondary winding and the load are located on a second side of the physical boundary (e.g., internal to the body). A primary voltage across the primary winding is regulated so as to provide a sufficiently stable output power to the load notwithstanding changes in the load and/or changes in a relative position of the primary winding and the secondary winding. One aspect of the invention relates to energy transfer methods and apparatus for use in connection with the human body. In particular, one example of the invention includes a transcutaneous energy transfer (TET) system for transferring power from a power supply external to the body to a device implanted in the body.

Abstract: An MRI-compatible, fixed-rate (VOO) pacemaker includes a self-contained power source housed at the proximal end of a photonic catheter in a first enclosure. Low energy continuous electrical power is delivered from the power source. This electrical power is converted into light energy and directed into the proximal end of the photonic catheter. The photonic catheter includes an optical conduction pathway over which is formed a covering of biocompatible material. Light entering the proximal end of the photonic catheter is transmitted through the optical conduction pathway, where it is collected and converted back to electrical energy at a second enclosure located at the distal end of the photonic catheter. The second enclosure houses a pulse generator that stores electrical energy and periodically releases that energy to deliver electrical pulses to bipolar heart electrodes.

Abstract: A controllable, wearable MRI-compatible, fixed-rate (VOO) pacemaker includes a self-contained steady state power source and an oscillator housed at the proximal end of a photonic catheter in a first enclosure. Continuous electrical energy is delivered from the power source and electrical pulses are delivered from the oscillator. The continuous electrical energy and electrical pulses are converted into respective continuous and pulsing light energy and directed into the proximal end of the photonic catheter. The photonic catheter includes optical conduction pathways and a covering of biocompatible material. Light entering the proximal end of the photonic catheter is transmitted through the optical conduction pathways, where it is collected and converted back to electrical energy at a second enclosure located at the distal end of the photonic catheter.

Abstract: A controllable, wearable MRI-compatible, fixed-rate (VOO) pacemaker includes a self-contained power source and a pulse generator housed at the proximal end of a photonic catheter in a first enclosure designed to operate externally of a patient's body. Electrical pulses output by the pulse generator are converted into light energy and directed into the proximal end of the photonic catheter. The photonic catheter includes an optical conduction pathway over which is formed a covering of biocompatible material. Light entering the proximal end of the photonic catheter is transmitted through the optical conduction pathway, where it is collected and converted back to electrical energy at a second enclosure located at the distal end of the photonic catheter. The second enclosure houses an opto-electrical transducer that converts the optical pulses to electrical pulses and delivers them to bipolar heart electrodes.

Abstract: A cardiac pacing apparatus has a source of pacing pulses that are transmitted through the animal by a radio frequency signal. An electrode-stent is implanted in a blood vessel adjacent to the point at which stimulation is desired. The electrode-stent contains an electrical circuit that is tuned to the radio frequency signal and which responds to receipt of that signal by applying an electric current to tissue of the animal.

Abstract: An electromagnetic field source (EFS) for providing electromagnetic energy to a secondary coil, including two or more primary coils that each carry a time-varying current to produce an electromagnetic field, and a controller that selectively provides current to one or more primary coils based on their position with respect to the secondary coil. The secondary coil may be implanted in a human recipient and used to provide power for the operation of a medical device, such as an artificial heart or ventricular assist device. The invention also provides such a secondary coil and EFS, collectively referred to as a transcutaneous energy transfer (TET) device. The primary coils of the EFS or TET may be housed in furniture. For example, they may be housed in a bed mattress or mattress pad on which the recipient rests, or in a blanket for covering the recipient.

Abstract: The invention provides a transcutaneous energy transfer device having an external primary coil and an implanted secondary coil inductively coupled to the primary coil, electronic components subcutaneously mounted within the secondary coil and a mechanism which reduces inductive heating of such components by the magnetic field of the secondary coil. For one embodiment of the invention, the mechanism for reducing inductive heating includes a cage formed of a high magnetic permeability material in which the electronic components are mounted, which cage guides the flux around the components to prevent heating thereof. For an alternative embodiment of the invention, a secondary coil has an outer winding and either a counter-wound inner winding or an inner winding in the magnetic field of the outer winding. For either arrangement of the inner coil, the inner coil generates a magnetic field substantially canceling the magnetic field of the outer coil in the area in which the electronic components are mounted.

Abstract: An implantable epicardial lead (13) is provided which is comprised of two spherical ICs (25) and (26) disposed at opposite ends of a supporting structure and separated by a predetermined distance. These spherical ICs comprise an anode and a cathode, each having connections thereto. The epicardial lead (13) includes circuitry for allowing inductive coupling of power into the epicardial lead (13) for storage in a capacitor (926). A switch (928) allows for selective discharge of the capacitor (926) to the surrounding myocardium into which it is implanted. The epicardial lead (13) also includes a receive/transmit device (942) for receiving command information for storage in a memory (939) to provide operation information therefor and also for receiving sensed information therefrom. The sensed information is sent via a switch (930).

Abstract: A medical system comprising a control device (referred to as a "planet") and a plurality of sensing and stimulating devices (referred to as "satellites") is disclosed. The satellites are relatively small devices that can be thoracoscopically attached to an exterior surface of the heart. The planet can be implanted if desired or, alternatively, externally retained. The planet is capable of wirelessly communicating (i.e., without a direct electrical connection) to each satellite. The planet individually commands each satellite to deliver pacing energy to the heart. Additionally, each satellite is capable of determining when a sense event has occurred at the site of that satellite and transmitting an encoded signal to the planet indicating that a sense event has occurred, along with an identifying code indicating to the planet which satellite detected the sense event.

Abstract: An external power head is energized by a motor causing movement of an element that produces a varying magnetic field, thereby inducing power in an implanted receiver coil within a patient's body. The external power head includes either one or more moving permanent magnets, or one or more moving elements that vary the magnetic flux coupled to the implanted receiver coil. As a result of the varying magnetic field experienced by the implanted receiver coil, an electric current flows from the implanted receiver coil to energize an implanted medical device.

Abstract: A connector apparatus system and method for providing a direct electrical connection to an implanted medical device for recharging batteries, reprogramming memory, or accessing data. The apparatus consists of a needle-like male connector in conjunction with an implantable female connector that is attached to the implanted medical device and contains a self-resealing elastomeric septum entry port. The female connector comprises a recepticle chamber that is densely packed with a plurality of randomly intertwining, thin, flexible, and conductive metal fibers. External battery charging equipment can be connected to the implanted medical device's internal battery with the connector apparatus system. The required circuit path for recharging can be completed by the use of two single polarity connector pairs, one single polarity connector pair in conjunction with a grounding plate, or one bipolar connector pair.

Abstract: An implantable system, such as a neural stimulator or a cochlear implant system, includes a rechargeable battery configuration having improved recharging and lifetime characteristics. The battery is housed within the implant's case and has first and second electrode plates. Each electrode plate has a plurality of slits that extend across a substantial portion of the plate's surface area. The slits in the electrode plates reduce the magnitude of eddy currents induced in the plates by external ac magnetic fields allowing faster battery recharging times. Alternatively, the electrode plates are wrapped in a spiral configuration such that, in the plane of the spiral, the electrode plates have a small cross-sectional area and no closed current loops. Additionally, the implant device may be housed in a case formed of a high-resistivity material and a circuit included in the implant device is configured to avoid large current loops that would result in eddy current heating.

Abstract: Magnetic Vector Steering (MVS) and Half-Cycle Amplitude Modulation (HCAM) are novel techniques which enhance the powering and control of multiple arbitrarily oriented implant devices. Together, these techniques enable arbitrarily oriented implants to receive power and command, programming, and control information in an efficient manner that preserves battery life and transmission time while reducing overall implant device bulk. By steering the aggregate magnetic field from a near-orthogonal set of AC-energized coils, selected implants can be powered or communicated with at desired times. Communication with individual implants can also be enhanced through half-cycle amplitude modulation--a technique that allows bit rates up to twice the energizing frequency. Unlike prior art systems, power and data transfer can be realized over the same frequency channel.

Abstract: A method and apparatus for providing electrical stimulation of the gastrointestinal tract. The apparatus features an implantable pulse generator which may be coupled to the gastric system through one or more medical electrical leads. In the preferred embodiment the leads couple to the circular layer of the stomach. The pulse generator preferably features sensors for sensing gastric electrical activity, and in particular, whether peristaltic contractions as occurring. In particular two sensors are featured. The first sensor senses low frequency gastrointestinal electrical activity between the frequency of 0.017-0.25 Hz and the second sensor senses intrinsic gastrointestinal electrical activity between the frequency of 100-300 Hz, which occurs upon normal peristaltic contractions. The second sensor only senses for a preset period after low frequency gastrointestinal electrical activity has been sensed by the first sensor.

Abstract: A self-cooling transcutaneous energy transfer system is provided for transmitting power to an implantable medical device, such as a defibrillator. The system includes a housing that is supported above the human body by a base so as to define a space between the housing and the body. A primary induction coil is disposed within the housing for transferring electromagnetic energy to the implantable medical device. A cooling fan is attached to the housing for providing forced convective heat transfer from the body. Various power and control circuitry are provided. The system can transfer away heat generated by eddy currents induced in the implantable device by the magnetic flux produced by the induction coil.

Abstract: An external power head is energized by a motor causing movement of an element that produces a varying magnetic field, thereby inducing power in an implanted receiver coil within a patient's body. The external power head includes either one or more moving permanent magnets, or one or more moving elements that vary the magnetic flux coupled to the implanted receiver coil. As a result of the varying magnetic field experienced by the implanted receiver coil, an electric current flows from the implanted receiver coil to energize an implanted medical device.

Abstract: A power control loop is established between an external control device and an implantable device so that only the amount of power needed by the implant device to sustain its present operating conditions is transmitted across a transcutaneous transmission link, thereby reducing the amount of power expended by the external control device. In one embodiment, the power control loop is used with a cochlea stimulating system that includes an externally wearable signal receiver and processor (WP) and an implanted cochlear stimulator (ICS). The power control loop is provided between the ICS and the WP such that power delivered to the ICS is precisely controlled in a closed loop manner, with a variable amount of RF energy (power) being transmitted across the transcutaneous link between the WP and ICS. The transmitted RF energy is received by the ICS and is converted to a voltage that is used as a power source within the ICS for stimulating electrode contacts of the ICS.

Abstract: There is provided an implantable system and method for delivering stimulus pulses and/or collecting data from a plurality of sites within a patient's body, having a main controller device with a power source, a stimulator/sensing devices at each of said sites, and circuitry for high frequency transmission of power from the main unit to each of the remote devices. Power is transferred by converting it into a high frequency at the controller unit, and periodically or on request transmitting it to the respective devices. The main controller unit and each respective device also preferably has one or more sensors for collecting data and processor circuitry for analyzing such data. Each remote device has a transmitter for transmitting collected data back to the main controller; the main controller has encoding circuitry for encoding a data component onto the high frequency carrier along with the power component.

Abstract: An energy transmission system for transmitting energy non-invasively from an external unit to an implanted medical device to recharge a battery in the medical device. An alternating magnetic field is generated by the external charging unit and a piezoelectric device in the implanted medical device vibrates in response to the magnetic flux to generate a voltage. The voltage is rectified and regulated to provide charging current to a rechargeable battery in the medical device. A series of piezoelectric devices may be connected in series to produce a larger voltage than can be produced by any one piezoelectric device. Acoustic waves generated by the external charging unit alternatively can be used to vibrate the piezoelectric device instead of a changing magnetic flux. The acoustic waves are generated by an external source coupled to a piezoelectric transducer.

Abstract: The implantable, electrically operated medical device system comprises an implantable radio frequency (RF) receiver and an external RF transmitter. The receiver has a receiving antenna and electronic circuitry coupled to the receiving antenna and includes a microcontroller having an output, a non-volatile memory coupled to the microcontroller and an implanted, electrically and autonomously operated medical device is coupled to the output of the microcontroller. The external RF transmitter has a power source and a transmitting antenna. The receiver further includes circuitry coupled to the microcontroller for regulating the power transmitted by the transmitter, whereby, RF energy can be transmitted by the transmitter and coupled into the receiver and the level of RF energy transmitted by the transmitter is controlled by the circuitry.

Abstract: The implantable, electrically operated medical device system comprises an implanted radio frequency (RF) receiving unit (receiver) incorporating a back-up rechargeable power supply and an implanted, electrically operated device, and an external RF transmitting unit (transmitter). RF energy is transmitted by the transmitter and is coupled into the receiver which is used to power the implanted medical device and/or recharge the back-up power supply. The back-up power supply within the receiver has enough capacity to be able to, by itself, power the implanted device coupled to the receiver for at least 24 hours during continual delivery of medical therapy. The receiver is surgically implanted within the patient and the transmitter is worn externally by the patient. The transmitter can be powered by either a rechargeable or non-rechargeable battery. In a first mode of operation, the transmitter will supply power, via RF coupled energy, to operate the receiver and simultaneously recharge the back-up power supply.

Abstract: A data communication system for control of transcutaneous energy transmission to an implantable medical device is disclosed having an implantable medical device with rechargeable batteries and a single coil that is employed both for energy transmission and data telemetry. Control circuitry in the implantable device senses battery voltage and current through the battery, encodes those values by use of a multiplexer, and transmits the sensed and encoded values through the coil to an external energy transmission device. The external device includes a coil that is electromagnetically coupled to the coil in the implantable device for receiving the encoded signals and for transmitting energy to the implantable device. The external device decodes the transmitted values and transmits those to a controller for controlling energy transmission.

Abstract: An improved transcutaneous energy transmission device is disclosed for charging rechargeable batteries in an implanted medical device and to minimize peak temperature rises in the implanted device. A current with a sinusoidal waveform is applied to a resonant circuit comprising a primary coil and a capacitor. Current is induced in a secondary coil attached to the implanted medical device. Two solid state switches are used to generate the sinusoidal waveform by alternately switching on and off input voltage to the resonant circuit. The present invention charges the batteries using a charging protocol that either reduces instantaneous charging current or duty cycle of a fixed charging current as the charge level in the battery increases. Peak temperature rises are less while delivering comparable electrical charge of the battery than for prior charging systems.

Abstract: Disclosed is a quick change battery drawer for rapidly substituting a fresh battery for an exhausted battery in the battery drawer of an external, battery powered therapeutic electrical stimulator while the stimulator continues to emit electrical stimulation to treat a patient. A push button is normally biased outward and a release member latches the battery drawer in the latched position through the interaction of first catches on the battery drawer and second catches on the release member. The terminals of a battery loaded in the battery drawer bear against and compress spring terminals that thereby spring load the battery drawer with a bias force and assist in keeping the battery drawer latched. When the release button is depressed, the first and second catches are disengaged, and the bias force acts to eject the battery and battery drawer forcefully into an ejected position where the battery drawer is prevented from completely ejecting from the side opening.