Boston Scientific Neuromodulation Corporation

Md Mizanur Rahman

Jordi Parramon

Robert Dai Ozawa

Kiran Nimmagadda

Rafael Carbunaru

Jeffery Van Funderburk

Robert R Tong

Joey Y Chen

Jess Weiqian Shi

Randy L Brase

Daniel Aghassian

Emanuel Feldman

Daniel Joseph Klostermann

Vasily Dronov

Gaurav Gupta

Compliance voltage generation circuitry for a medical device is disclosed. The circuitry in one embodiment comprises a boost converter and a charge pump, either of which is capable of generating an appropriate compliance voltage from the voltage of the battery in the device. A boost signal from compliance voltage monitor-and-adjust logic circuitry is processed with a telemetry enable signal to selectively enable either the charge pump or the boost converter: if the telemetry enable signal is not active, the boost converter is used to generate the compliance voltage; if the telemetry enable signal is active, the charge pump is used. Because the charge pump circuitry does not produce a magnetic field, the charge pump will not interfere with magnetically-coupled telemetry between the implant and an external controller. By contrast, the boost converter is allowed to operate during periods of no telemetry, when magnetic interference is not a concern.

Selectable boost converter and charge pump for compliance voltage generation in an implantable stimulator device

An electrical stimulation system provides stimulation therapy to a patient. The system includes a neurostimulation lead that contacts patient tissue and couples with an implantable stimulation device, such as an implantable pulse generator, that receives stimulation parameters for providing stimulation therapy to a patient. The implantable stimulation device includes a header with a plurality of connector assemblies that receive an end of the neurostimulation lead, and a case containing a charging coil and a telemetry coil coupled to programming circuitry on a printed circuit board, which is in turn coupled to the connector assemblies via a feedthrough assembly. The telemetry coil receives data from an external programmer and transmits the data to the programming circuitry, which in turn uses the data to communicate to the connector assemblies and the neurostimulation lead to provide stimulation therapy to a patient.

Implantable medical device for providing stimulation therapy

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.

Efficient external charger for an implantable medical device optimized for fast charging and constrained by an implant power dissipation limit

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.

Telemetry optimization in an implantable medical device system to achieve equal and maximal distances in bidirectional communications

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.

Efficient external charger for charging a plurality of implantable medical devices

Improved compliance voltage generation circuitry for a medical device is disclosed. The improved circuitry in one embodiment comprises a boost converter and a charge pump, either of which is capable of generating an appropriate compliance voltage from the voltage of the battery in the device. A telemetry enable signal indicating whether the implant's transmitter, receiver, or both, have been enabled is received. A 'boost' signal from compliance voltage monitor-and-adjust logic circuitry is processed with the telemetry enable signal and its inverse to selectively enable either the charge pump or the boost converter: if the telemetry enable signal is not active, the boost converter is used to generate the compliance voltage; if the telemetry enable signal is active, the charge pump is used. Because the charge pump circuitry does not produce a magnetic field, the charge pump will not interfere with magnetically-coupled telemetry between the implant and an external controller. By contrast, the boost converter is allowed to operate during periods of no telemetry, when magnetic interference is not a concern, while obtaining the advantage of higher power efficiency.

An implantable control module for an implantable electrical stimulation system includes a housing with at least a portion of the exterior forming a metallic structure and at least a portion of the interior defining a sealed compartment. The control module further includes an electronic subassembly disposed in the sealed compartment; a connector assembly coupled to the housing and defining a port for receiving a lead; connector contacts disposed in the port to electrically couple with terminals of the lead; feedthrough interconnects extending from the connector assembly into the sealed compartment and coupling the connector contacts to the electronic subassembly; and a coil disposed within or on the housing and configured and arranged to be shorted when an external electromagnetic field is applied in order to resist generation of an eddy current in the metallic structure of the exterior of the sealed housing in response to the external electromagnetic field.

Systems and methods for reducing electromagnetic field-induced heating from an implantable pulse generator

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.

Communication and charging circuitry for a single-coil implantable medical device

An improved implantable pulse generator (IPG) containing improved telemetry circuitry is disclosed. The IPG includes a telemetry coil within the conductive IPG case, not in the non-conductive header as is typical, which simplifies IPG design. The improved resonant circuit of which the coil is a part does not include a discrete tuning resistor with the coil, which tuning resistor was traditionally used to increase communication bandwidth of the coil to render it suitable for FSK telemetry. In lieu of the tuning resistor, the coil is intentionally inductively coupled to the case by positioning the coil a certain distance away from the case. Such coupling decreases the effective inductance and increases the effective series resistance in the improved resonant circuit, both of which increase the communication bandwidth. As such, suitable FSK telemetry can be achieved, even though the improved resonant circuit without the case would not on its own have suitable bandwidth.

Using the case of an implantable medical device to broaden communication bandwidth

An improved implantable pulse generator (IPG) containing improved telemetry circuitry is disclosed. The IPG includes charging and telemetry coils within the IPG case, which increases their mutual inductance and potential to interfere with each other; particularly problematic is interference to the telemetry coil caused by the charging coil. To combat this, improved telemetry circuitry includes decoupling circuitry for decoupling the charging coil during periods of telemetry between the IPG and an external controller. Such decoupling circuitry can comprise use of pre-existing LSK circuitry during telemetry, or new discrete circuitry dedicated to decoupling. The decoupling circuitry is designed to prevent or at least reduce induced current flowing through the charging coil during data telemetry. The decoupling circuitry can be controlled by the microcontroller in the IPG, or can automatically decouple the charging coil at appropriate times to mitigate an induced current without instruction from the microcontroller.

Growing community of inventors

Stevenson Ranch, CA, United States of America

Md Mizanur Rahman