Boston Scientific Neuromodulation Corporation

Advanced Bionics Corporation

Boston Science Neuromodulation Corporation

Yuping He

David K L Peterson

Jordi Parramon

Kiran Nimmagadda

Emanuel Feldman

Que T Doan

Jess Weiqian Shi

Goran Nils Marnfeldt

Robert Dai Ozawa

Jess Weigian Shi

Dave Peterson

Joey Y Chen

Rankiri Tissa Karunasiri

Jie Yan

David L Peterson

David KL Peterson

Emmanuel Feldman

Goran N Marnfeldt

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

Circuitry useable to protect and reliably charge a rechargeable battery, even from a zero-volt state, is disclosed, and is particularly useful when employed in an implantable medical device. The circuit includes two charging paths, a first path for trickle charging the battery, and a second path for charging the battery at relatively higher currents. A passive diode is used in the first trickle-charging path which allows trickle charging even when the battery voltage is too low for reliable gating, while a gateable switch (preferably a PMOS transistor) is used in the second higher-current charging path when the voltage is higher and the switch can therefore be gated more reliably. A second diode between the two paths ensures no leakage to the substrate through the gateable switch during trickle charging. The load couples to the battery through the switch, and preferably through a second switch specifically used for decoupling the load.

Battery protection and zero-volt battery recovery system for an implantable medical device

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.

Current output architecture for an implantable stimulator device

Circuitry useable to protect and reliably charge a rechargeable battery, even from a zero-volt state, is disclosed, and is particularly useful when employed in an implantable medical device. The circuit includes two charging paths, a first path for trickle charging the battery at a relatively low current when the battery voltage is below a threshold, and a second path for charging the battery at relatively higher currents that the battery voltage is above a certain threshold. A passive diode is used in the first trickle-charging path which allows trickle charging even when the battery voltage is too low for reliable gating, while a gateable switch (preferably a PMOS transistor) is used in the second higher-current charging path when the voltage is higher and the switch can therefore be gated more reliably. A second diode between the two paths ensures no leakage to the substrate through the gateable switch during trickle charging. The load couples to the battery through the switch, and preferably through a second switch specifically used for decoupling the load.

Battery management circuitry for an implantable medical device such as an implantable neurostimulator is described. The circuitry has a T-shape with respect to the battery terminal, with charging circuitry coupled between rectifier circuitry and the battery terminal on one side of the T, and load isolation circuitry coupled between the load and the battery terminal on the other side. The load isolation circuitry can comprise two switches wired in parallel. An undervoltage fault condition opens both switches to isolate the battery terminal from the load to prevent further dissipation of the battery. Other fault conditions will open only one the switches leaving the other closed to allow for reduced power to the load to continue implant operations albeit at safer low-power levels. The battery management circuitry can be fixed in a particular location on an integrated circuit which also includes for example the stimulation circuitry for the electrodes.

Battery management for an implantable medical 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

Disclosed herein are methods and circuitry for monitoring and adjusting a compliance voltage in an implantable stimulator devices to an optimal value that is sufficiently high to allow for proper circuit performance (i.e., sufficient current output), but low enough that power is not needlessly wasted via excessive voltage drops across the current output circuitry. The algorithm measures output voltages across the current source and sink circuitry during at least periods of actual stimulation when both the current sources and sinks are operable, and adjusts the compliance voltage so as to reduce these output voltages to within guard band values preferably indicative for operation in transistor saturation. The output voltages can additionally be monitored during periods between stimulation pulses to improve the accuracy of the measurement, and is further beneficial in that such additional measurements are not perceptible to the patient.

Techniques for sensing and adjusting a compliance voltage in an implantable stimulator device

An implantable device includes a stimulation electronic circuit, a battery, a receiver configured to receive energy from a source external to the implantable stimulation device, and a battery charger circuit configured to use the energy to charge the battery and power the stimulation electronic circuit, the battery charger circuit including a load switch for connecting/disconnecting the battery, the load switch being controlled by the stimulation electronic circuit.

Growing community of inventors

Northridge, CA, United States of America

Yuping He