Abstract: A therapeutic neuromodulation system configured for providing therapy to a patient. The therapeutic neuromodulation system comprises a plurality of electrical terminals configured for being respectively coupled to a plurality of electrodes implanted within tissue, analog output circuitry configured for delivering therapeutic electrical energy between the plurality of electrical terminals in accordance with a set of modulation parameters that includes a defined current value, a voltage regulator configured for supplying an adjustable compliance voltage to the analog output circuitry, and control/processing circuitry configured for automatically performing a compliance voltage calibration process at a compliance voltage adjustment interval by periodically computing an adjusted compliance voltage value as a function of a compliance voltage margin.

Abstract: An implantable microstimulator configured for implantation beneath a patient's skin for tissue stimulation to prevent and/or treat various disorders, uses a self-contained power source. Periodic or occasional replenishment of the power source is accomplished, for example, by inductive coupling with an external device. A bidirectional telemetry link allows the microstimulator to provide information regarding the system's status, including the power source's charge level, and stimulation parameter states. Processing circuitry automatically controls the applied stimulation pulses to match a set of programmed stimulation parameters established for a particular patient. The microstimulator preferably has a cylindrical hermetically sealed case having a length no greater than about 27 mm and a diameter no greater than about 3.3 mm. A reference electrode is located on one end of the case and an active electrode is located on the other end.

Abstract: A neuromodulation system and method of providing sub-threshold modulation therapy. Electrical modulation energy is delivered to a target tissue site of the patient at a programmed intensity value, thereby providing therapy to a patient without perception of stimulation. In response to an event, electrical modulation energy is delivered at incrementally increasing intensity values. At least one evoked compound action potential (eCAP) is sensed in a population of neurons at the target tissue site of the patient in response to the delivery of the electrical modulation energy at the incrementally increasing intensity values. One of the incrementally increased intensity values is selected based on the sensed eCAP(s). A decreased intensity value is automatically computed as a function of the selected intensity value. Electrical modulation energy is delivered to the target tissue site of the patient at the computed intensity value, thereby providing sub-threshold therapy to the patient.

Abstract: An implantable microstimulator configured for implantation beneath a patient's skin for tissue stimulation to prevent and/or treat various disorders, uses a self-contained power source. Periodic or occasional replenishment of the power source is accomplished, for example, by inductive coupling with an external device. A bidirectional telemetry link allows the microstimulator to provide information regarding the system's status, including the power source's charge level, and stimulation parameter states. Processing circuitry automatically controls the applied stimulation pulses to match a set of programmed stimulation parameters established for a particular patient. The microstimulator preferably has a cylindrical hermetically sealed case having a length no greater than about 27 mm and a diameter no greater than about 3.3 mm. A reference electrode is located on one end of the case and an active electrode is located on the other end.

Abstract: A neuromodulation system and method of providing therapy to a patient. Electrical energy is delivered to the patient in accordance with a modulation parameter, thereby providing therapy to the patient, and the modulation parameter of the delivered electrical energy is varied over a period of time, such that the delivered electrical energy is continually maintained at a sub-threshold level throughout the period of time. The sub-threshold level may be referred to as a patient-perception threshold, which may be referred to as a boundary below which a patient does not sense delivery of the electrical energy. For example, in a spinal cord modulation system, the patient-perception threshold may be a boundary below which a patient does not experience paresthesia.

Abstract: A method for configuring stimulation pulses in an implantable stimulator device having a plurality of electrodes is disclosed, which method is particularly useful in adjusting the electrodes by current steering during initialization of the device. In one aspect, a set of ideal pulses for patient therapy is determined, in which at least two of the ideal pulses are of the same polarity and are intended to be simultaneous applied to corresponding electrodes on the implantable stimulator device during an initial duration. These pulses are reconstructed into fractionalized pulses, each comprised of pulse portions. The fractionalized pulses are applied to the corresponding electrodes on the device during a final duration, but the pulse portions of the fractionalized pulses are not simultaneously applied during the final duration.

Abstract: A combination charging and telemetry circuit for use within an implantable device, such as a microstimulator, uses a single coil for both charging and telemetry. In accordance with one aspect of the invention, one or more capacitors are used to tune the single coil to different frequencies, wherein the coil is used for multiple purposes, e.g., for receiving power from an external source and also for the telemetry of information to and from an external source.

Abstract: Electrode voltage monitoring circuitry for an implantable neurostimulator system having a plurality of electrode-driver integrated circuits (ICs) in provided. Electrodes from either or both ICs can be chosen to provide stimulation, and one of the IC acts as the master while the other acts as the slave. Electrodes voltages on the slave IC are routed to the master IC, and thus the master IC can monitor both electrode voltages on the slave as well as electrode voltages on the master. Such voltages can be monitored for a variety of purposes, and in particular use of such voltage is disclosed for determining the resistance between electrodes and to set a compliance voltage for stimulation.

Abstract: An external control device and method for programming an implantable neuromodulator coupled to an electrode array implanted adjacent tissue of a patient having a medical condition. Electrical modulation energy is conveyed to tissue of the patient in accordance with a series of modulation parameter sets. The patient perceives paresthesia in response to the conveyance of the electrical modulation energy to the tissue in accordance with at least one of the modulation parameter sets. One of the modulation parameter set(s) is identified based on the perceived paresthesia. Another modulation parameter set is derived from the identified modulation parameter set. Electrical modulation energy is conveyed to the tissue of the patient in accordance with the other modulation parameter set without causing the patient to perceive paresthesia.

Abstract: An implantable stimulation device that includes output current sources and/or sinks configured to provide an output current for a load (i.e., tissue). The output path of the output current source or sink comprises a transistor which operates in a linear mode instead of a saturation mode. Because operation in a linear mode results in smaller drain-to-source voltage drops, power consumption in the output current source or sink (and hence in the implantable stimulator) is reduced, reducing battery or other power source requirements. Operation in the linear mode is facilitated by a load in an input path and a load in the output path (which bears the output current). The loads can be active transistors or passive resistors. A feedback circuit (e.g., an operational amplifier) receives voltages that build up across these loads, and sends a control signal to the gate of the transistor to ensure its linear operation.

Abstract: An external charger for a battery in an implantable medical device and charging techniques are disclosed. Simulation data is used to model the power dissipation of the charging circuitry in the implant at varying levels of implant power. A power dissipation limit constrains the charging circuitry from producing an inordinate amount of heat to the tissue surrounding the implant, and duty cycles of a charging field are determined so as not to exceed that limit. A maximum simulated average battery current determines the optimal (i.e., quickest) battery charging current, and at least an optimal value for a parameter indicative of that current is determined and stored in the external charger. During charging, the actual value for that parameter is determined, and the intensity and/or duty cycle of the charging field are adjusted to ensure that charging is as fast as possible, while still not exceeding the power dissipation limit.

Abstract: Timer circuitry completely formable in an integrated circuit (IC) for generating a clock signal in an implantable medical device is disclosed. The timer circuitry can be formed on the same Application Specific Integrated Circuit typically used in the implant, and requires no external components. The timer circuitry comprises modification to a traditional astable timer circuit. A resistance in the disclosed timer circuit can be trimmed to adjust the frequency of the clock signal produced, thus allowing that frequency to be set to a precise value during manufacturing. Precision components are not needed in the RC circuit, which instead are used to set the rough value of the frequency of the clock signal. A regulator produces a power supply for the timer circuitry from a main power supply (Vcc), producing a clock signal with a frequency that is generally independent of temperature and Vcc fluctuations.

Abstract: An implantable microstimulator configured to be implanted beneath a patient's skin for tissue stimulation employs a bi-directional RF telemetry link for allowing data-containing signals to be sent to and from the implantable microstimulator from at least two external devices. Further, a separate electromagnetic inductive telemetry link allows data containing signals to be sent to the implantable microstimulator from at least one of the two external devices. The RF bidirectional telemetry link allows the microstimulator to inform the patient or clinician regarding the status of the microstimulator device, including the charge level of a power source, and stimulation parameter states. The microstimulator has a cylindrical hermetically sealed case having a length no greater than about 27 mm and a diameter no greater than about 3.3 mm. A reference electrode is located on one end of the case and an active electrode is located on the other end of the case.

Abstract: A method for configuring stimulation pulses in an implantable stimulator device having a plurality of electrodes is disclosed, which method is particularly useful in adjusting the electrodes by current steering during initialization of the device. In one aspect, a set of ideal pulses for patient therapy is determined, in which at least two of the ideal pulses are of the same polarity and are intended to be simultaneous applied to corresponding electrodes on the implantable stimulator device during an initial duration. These pulses are reconstructed into fractionalized pulses, each comprised of pulse portions. The fractionalized pulses are applied to the corresponding electrodes on the device during a final duration, but the pulse portions of the fractionalized pulses are not simultaneously applied during the final duration.

Abstract: An external charger for a battery in an implantable medical device (implant), and technique for charging batteries in multiple implants using such improved external charger, is disclosed. During charging, values for a parameter measured in the implants are reported from the implants to the external charger. The external charger infers from the magnitudes of the parameters which of the implants has the highest (hot) and lowest (cold) coupling to the external charger. The intensity of the magnetic charging field is optimized for the cold implant to ensure that it is charged with a maximum (fastest) battery charging current. The duty cycle of the magnetic charging field is also optimized for the hot implant to ensure that it does not exceed a power dissipation limit. As a result, charging is optimized to be fast for all of the implants, while still safe from a tissue heating perspective.

Abstract: A combination charging and telemetry circuit for use within an implantable device, such as a microstimulator, uses a single coil for both charging and telemetry. In accordance with one aspect of the invention, one or more capacitors are used to tune the single coil to different frequencies, wherein the coil is used for multiple purposes, e.g., for receiving power from an external source and also for the telemetry of information to and from an external source.

Abstract: Disclosed herein are current output architectures for implantable stimulator devices. Current source and sink circuitry is divided into a plurality of stages, each of which is capable via an associated switch bank of sourcing or sinking an amount of current to or from any one of the electrodes of the device. The current source circuitry is distinct from the current sink circuitry, and the two share no common circuit nodes prior to connection to the electrodes. In other words, the current source circuitry and the current sink circuitry do not share a common node other than the electrodes. Each stage is preferably formed of a current mirror for receiving a reference current and outputting a scaled version of current to that stage's switch bank. The scalar at each stage can be set by wiring a desired number of output transistors in parallel.

Abstract: Electrode voltage monitoring circuitry for an implantable neurostimulator system having a plurality of electrode-driver integrated circuits (ICs) in provided. Electrodes from either or both ICs can be chosen to provide stimulation, and one of the IC acts as the master while the other acts as the slave. Electrodes voltages on the slave IC are routed to the master IC, and thus the master IC can monitor both electrode voltages on the slave as well as electrode voltages on the master. Such voltages can be monitored for a variety of purposes, and in particular use of such voltage is disclosed for determining the resistance between electrodes and to set a compliance voltage for stimulation.

Abstract: Communication and charging circuitry for an implantable medical device is described having a single coil for receiving charging energy and for data telemetry. The circuitry removes from the AC side of the circuit a tuning capacitor and switch traditionally used to tune the tank circuitry to different frequencies for telemetry and charging. As such, the tank circuitry is simplified and contains no switchable components. A switch is serially connected to the storage capacitor on the DC side of the circuit. During telemetry, the switch is opened, thus disconnecting the storage capacitor from the tank circuit, and alleviating concerns that this capacitor will couple to the tank circuit and interfere with telemetry operations. During charging, the switch is closed, which allows the storage capacitor to couple to the tank circuitry through the rectifier during some portions of the tank circuitry's resonance.

Abstract: Methods and circuitry for determining an implanted-neurostimulator patient's position, and adjusting a situation program delivered by the neurostimulator based on the determined position, is disclosed. Impedance measurements of the patient's tissue are taken at the neurostimulator's electrodes, which measurements can comprise complex impedance measurements (magnitude and phase) taken at different frequencies. Such impedance measurements, which can be taken interleaved with stimulation therapy, are used to determine an “impedance fingerprint.” This fingerprint can be compared to other known fingerprints stored in the IPG, which known fingerprints are associated with particular stimulation programs. When a measured fingerprint matches one stored in the IPG, the stimulation program associated with the stored fingerprint is automatically used for patient therapy.