Boston Scientific Neuromodulation Corporation

Boston Science Neuromodulation Corporation

Kiran Nimmagadda

Jordi Parramon

Emanuel Feldman

Yuping He

Md Mizanur Rahman

Goran Nils Marnfeldt

Daniel Aghassian

Jess Weiqian Shi

Paul James Griffith

Emmanuel Feldman

Disclosed herein are circuits and methods for a multi-electrode implantable stimulator device incorporating one decoupling capacitor in the current path established via at least one cathode electrode and at least one anode electrode. In one embodiment, the decoupling capacitor may be hard-wired to a dedicated anode on the device. The cathodes are selectively activatable via stimulation switches. In another embodiment, any of the electrodes on the devices can be selectively activatable as an anode or cathode. In this embodiment, the decoupling capacitor is placed into the current path via selectable anode and cathode stimulation switches. Regardless of the implementation, the techniques allow for the benefits of capacitive decoupling without the need to associate decoupling capacitors with every electrode on the multi-electrode device, which saves space in the body of the device. Although of particular benefit when applied to microstimulators, the disclosed technique can be used with space-saving benefits in any stimulator device.

Multi-electrode implantable stimulator device with a single current path decoupling capacitor

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 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.

Low power loss current digital-to-analog converter used in an implantable pulse generator

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 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.

Minimizing interference between charging and telemetry coils in an implantable medical device

In one embodiment, the present invention provides 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 in useful embodiments by a load in an input path (into which a reference current is sent) 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.

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 communicate 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 without the need for a major redesign of the main IPG IC.

Architectures for an implantable medical device system

An improved transceiver circuit particularly useful in an inductively coupled wireless communication system such as an implantable medical device system is disclosed. The improved transceiver circuit is switchable to assume a serial L-C configuration in the transmit mode and a parallel L-C configuration in the receive mode, but does not require high voltage switches. A low-drive transmitter and a high-input-impedance receiver are used, which reduces power consumption in receive mode, while still maintaining good transmitter performance.

Growing community of inventors

Valencia, CA, United States of America

Kiran Nimmagadda