Abstract: Receiver and digital demodulation circuitry for an external controller for communicating with an implantable medical device (IMD) is disclosed. A Digital Signal Processor (DSP) is used to sample received analog data transmitted from the IMD at a lower rate than would otherwise be required for the frequency components in the transmitted data by the Nyquist sampling criteria. To allow for this reduced sampling rate, the incoming data is shifted to a lower intermediate frequency using a switching circuit. The switching circuit receives a clock signal, which is preferably but not necessarily the same clock signal used by the DSP to sample the data. The switching circuit multiplies the received data with the clock signal to produce lower intermediate frequencies, which can then be adequately sampled at the DSP at the reduced sampling rate per the Nyquist sampling criteria.

Abstract: The disclosed means of determining alignment between an external charger and an implantable medical device (IMD) involves the use of reflected impedance modulation, i.e., by measuring at the external charger reflections arising from modulating the impedance of the charging coil in the IMD. During charging, the charging coil in the IMD is pulsed to modulate its impedance. The difference in the coil voltage (?V) produced at the external charger as a result of these pulses is assessed and is used by the external charger to indicate coupling. If the magnitude of ?V is above a threshold, the external charger considers the coupling to the IMD to be adequate, and an alignment indicator in the external charger is controlled accordingly. The magnitude of Vcoil can be assessed in addition to ?V to determine alignment with the IMD with improved precision, and/or to further define a high quality alignment condition.

Abstract: Disclosed is a charging coil assembly for a mobile device able to wirelessly provide power to charge a battery in an Implantable Medical Device (IMD). The assembly includes a coaxial connector that can be inserted into a coaxial audio port on the mobile device to allow bi-directional communications between the assembly and the mobile device. One or more housings coupled to the connector by a cable can include control circuitry, a charging coil, and a battery. The charging coil can be driven by control circuitry in the assembly or by a charging audio signal at an audio frequency provided by the mobile device via the audio port and connector. A Charging Application on the mobile device can detect and authenticate the charging coil assembly, and render a charging graphical user interface on the mobile device to control and/or monitor charging of the IMD.

Abstract: An external charging system for charging or powering an implantable medical device is disclosed which is self-affixing to the patient without the need for a holding device. The charging system can comprise a charging coil attached to a flexible member. The flexible member is bendable, and when bent will firmly hold its position on the patient. The system can include an electronics module including a user interface and the necessary electronics for activating the charging coil to produce a magnetic charging field. Wires can couple the charging coil in the coil module to the electronics in the electronics modules. The entire assembly can be encased in a water proof sleeve having a high-friction surface, which protects the charging system and helps the charging system to adhere to the patient.

Abstract: Disclosed are an external charger including a solar cell array for charging or powering an implantable medical device (IMD), and a cradle including a solar cell array for charging or powering an external charger for charging or powering an implantable medical device. The disclosed improved external charger or improved cradle are particularly beneficial for charging a battery in an external charger used to charge or power an IMD when a power source is otherwise unavailable, such as a wall socket.

Abstract: The disclosed system for providing closed loop charging between an external charger and an implantable medical device such as an IPG involves the use of reflected impedance modulation, i.e., by measuring at the external charger reflections arising from modulating the impedance of the charging coil in the IPG. During charging, the charging coil in the IPG is periodically pulsed to modulate its impedance. The magnitude of the change in the coil voltage produced at the external charger ?V as a result of these pulses is assessed and is used by the controller circuitry in the external charger as indicative of the coupling between the external charger and the IPG. The external charger adjusts its output power (e.g., Icharge) in accordance with the magnitude of ?V, thus achieving closed loop charging without the need of telemetering coupling parameters from the IPG.

Abstract: Methods for optimizing telemetry in an implantable medical device system are disclosed, with the goal of equating and maximizing the communication distances between devices in the system, such as the external controller and the Implantable Pulse Generator (IPG). The method involves computerized simulation of maximum communication distances in both directions between the two devices while varying at least two parameters of the telemetry circuitry, such as the number of turns in the telemetry coils in the two devices. This results in a simulation output comprising a matrix in which each element comprises the bidirectional distance values. An element is determined for which the distances are equal (or nearly equal) and maximized (or nearly maximized), and the optimal values for the parameters are then chosen on that basis, with the result that the communication distance in one direction equals the communication distance in the other direction, and is maximized.

Abstract: An external controller/charger system for an implantable medical device is disclosed, in which the external controller/charger system provides automatic switching between telemetry and charging without any manual intervention by the patient. The external controller/charger system includes an external controller which houses a telemetry coil and an external charging coil coupled to the external controller. Normally, a charging session is carried out using the external charging coil, and a telemetry session is carried out using the telemetry coil. However, when a patient requests to carry out telemetry during a charging session, the external charging coil is used instead of the internal telemetry coil.

Abstract: An integrated external controller/charger system for an implantable medical device is disclosed comprising an external controller/charger device with a Graphical User Interface (GUI) and first battery, and an external charging coil assembly coupleable to the external controller/charger device and including or associated with a second battery. The second battery is used to energize a charging coil in the external charging coil assembly, while the first battery is used to power other aspects of the system (data telemetry circuitry, control circuitry, the GUI, etc.). Because the second battery powers the relatively high-power charging function, the first battery in the external controller/charger device can be made smaller. Additionally, the second battery enables a suitable external controller device (e.g. a mobile device such as a cell phone) to provide charging functionality even if its first battery is otherwise inadequate.

Abstract: Electrical energy is transcutaneously transmitted at a plurality of different frequencies to an implanted medical device. The magnitude of the transmitted electrical energy respectively measured at the plurality of frequencies. One of the frequencies is selected based on the measured magnitude of the electrical energy (e.g., the frequency at which the measured magnitude of the electrical energy is the greatest). A depth level at which the medical device is implanted within the patient is determined based on the selected frequency. For example, the depth level may be determined to be relatively shallow if the selected frequency is relatively high, and relatively deep if the selected frequency is relative low. A charge strength threshold at which a charge strength indicator generates a user-discernible signal can then be set based on the determined depth level.

Abstract: An improved external trial stimulator provides neurostimulation functionality for implanted medical electrodes prior to implantation of an implantable neurostimulator. The external trial stimulator is housed in a four-part housing that provides mechanical and electrostatic discharge protection for the electronics mounted in a central frame of the housing. Connectors attached to leads from the electrodes connect to contacts that are recessed in the housing through ports that are centered for easy access. Multiple indicators provide information to users of the external trial stimulator.

Abstract: The disclosed system for providing closed loop charging between an external charger and an implantable medical device such as an IPG involves the use of reflected impedance modulation, i.e., by measuring at the external charger reflections arising from modulating the impedance of the charging coil in the IPG. During charging, the charging coil in the IPG is periodically pulsed to modulate its impedance. The magnitude of the change in the coil voltage produced at the external charger ?V as a result of these pulses is assessed and is used by the controller circuitry in the external charger as indicative of the coupling between the external charger and the IPG. The external charger adjusts its output power (e.g., Icharge) in accordance with the magnitude of ?V, thus achieving closed loop charging without the need of telemetering coupling parameters from the IPG.

Abstract: Disclosed in an improved medical implantable device system including an improved external charger that is able to communicate with an external controller and IPG using the communication protocol (e.g., FSK) used to implement communications between the external controller and the implant. The external controller as modified uses its charging coil to charge the implant, and also to communicate with the other devices in the system. As such, the external charger is provided with transceiver circuitry operating in accordance with the protocol, and also includes tuning circuitry to tune the coil as necessary for communications or charging. Communication or charging access to the charging coil in the external charger is time multiplexed. The disclosed system allows charging information to be provided to the user interface of the external controller so that it can be reviewed by the user, who may take corrective action if necessary.

Abstract: An improved architecture for an implantable medical device such as an implantable pulse generator (IPG) is disclosed. In one embodiment, the various functional blocks for the IPG are incorporated into a signal integrated circuit (IC). Each of the functional blocks communicates with each other, and with other off-chip devices if necessary, via a centralized bus governed by a communication protocol. To communicate with the bus and to adhere to the protocol, each circuit block includes bus interface circuitry adherent with that protocol. Because each block complies with the protocol, any given block can easily be modified or upgraded without affecting the design of the other blocks, facilitating debugging and upgrading of the IPG circuitry. Moreover, because the centralized bus can be taken off the integrated circuit, extra circuitry can easily be added off chip to modify or add functionality to the IPG.

Abstract: An external controller/charger system for an implantable medical device is disclosed, in which the external controller/charger system provides automatic switching between telemetry and charging without any manual intervention by the patient. The external controller/charger system includes an external controller which houses a telemetry coil and an external charging coil coupled to the external controller. Normally, a charging session is carried out using the external charging coil, and a telemetry session is carried out using the telemetry coil. However, when a patient requests to carry out telemetry during a charging session, the external charging coil is used instead of the internal telemetry coil.

Abstract: An improved external trial stimulator provides neurostimulation functionality for implanted medical electrodes prior to implantation of an implantable neurostimulator. The external trial stimulator is housed in a four-part housing that provides mechanical and electrostatic discharge protection for the electronics mounted in a central frame of the housing. Connectors attached to leads from the electrodes connect to contacts that are recessed in the housing through ports that are centered for easy access. Multiple indicators provide information to users of the external trial stimulator.

Abstract: An external charger for an implantable medical device is disclosed which can automatically detect an implant and generate a charging field. The technique uses circuitry typically present in an external charger, such as control circuitry, a Load Shift Keying (LSK) demodulator, and a coupling detector. An algorithm in the control circuitry periodically issues charging fields of short duration in a standby mode. If the coupling detector detects the presence of a conductive material, the algorithm issues a listening window during which a charging field is generated. If an LSK reply signal is received at the LSK demodulator, the external charger can charge the implant in a normal fashion. If a movement signature is detected at the LSK demodulator indicative of a predetermined user movement of the external charger, a charging field is issued for a set timing period, to at least partially charge the IPG battery to restore LSK communications.

Abstract: An improved implantable medical device system having dual coils in one of the devices in the system is disclosed. The dual coils are used preferably in an external device such as an external controller or an external charger. The dual coils are wrapped around axes that are preferably orthogonal, although other non-zero angles could be used as well. When used to transmit, the two coils are driven (for example, with FSK-modulated data when the transmitting data) out of phase, preferably at 90 degrees out of phase. This produces a magnetic field which rotates, and which reduces nulls in the coupling between the external device and the receiving coil within the implanted device. Moreover, implementation of the dual coils to transmit requires no change in the receiver circuitry of the implanted device. Should the device with dual coils also receive transmissions from the other device (e.g.

Abstract: Electrical energy is transcutaneously transmitted at a plurality of different frequencies to an implanted medical device. The magnitude of the transmitted electrical energy respectively measured at the plurality of frequencies. One of the frequencies is selected based on the measured magnitude of the electrical energy (e.g., the frequency at which the measured magnitude of the electrical energy is the greatest). A depth level at which the medical device is implanted within the patient is determined based on the selected frequency. For example, the depth level may be determined to be relatively shallow if the selected frequency is relatively high, and relatively deep if the selected frequency is relative low. A charge strength threshold at which a charge strength indicator generates a user-discernible signal can then be set based on the determined depth level.

Abstract: An improved external charger for an implantable medical device is disclosed in which charging is at least partially controlled based on a determined position of the external charger, which position may be indicative of the pressure between the external charger and a patient's tissue. The improved external charger includes one or more position determination elements, e.g., an accelerometer or gyrometer, and control circuitry for controlling the external device in accordance with the determined position. The determined position of the external charger can be used to control charging, for example, by suspending charging, by adjusting the intensity of charging, by adjusting a maximum set point temperature for the external charger, or issuing an alert via a suitable user interface. By so controlling the external charger on the basis of the determined position, the external charger is less likely to create potentially problematic or uncomfortable conditions for the user.