Alfred E. Mann Foundation for Scientific Research

Edward K F Lee

Harshit R Suri

Eusebiu Matei

Brian R Dearden

A multiple output current stimulator circuit with fast turn on time is described. At least one pair of input side and output side transistors is arranged in a current mirror connected to a supply transistor by cascode coupling. The output side transistor supplies stimulation current to an electrode in contact with tissue. An operational amplifier connected to a reference voltage and to the output side transistor drives the supply transistor to maintain the voltage at the output side transistor equal to the reference voltage. The at least one pair of transistors includes multiple pairs of transistors whose output side transistors drive respective electrodes with stimulation currents. The stimulator determines the initiation and duration of stimulation current pulses supplied to each electrode. At circuit activation, large currents are generated which discharge capacitances in the output side transistors causing rapid output side transistor turn on.

Current sensing multiple output current stimulators

A medical system and method of communicating between a telemetry controller and medical devices is provided. Coupling coefficients between a primary coil of the telemetry controller and secondary coils of the medical devices differ from each other. A primary carrier signal is applied to the primary coil, thereby respectively inducing secondary carrier signals on the secondary coils. An amplitude of the secondary carrier signal is measured on each of the secondary coils. The envelope of each secondary carrier signal is modulated in accordance with data, thereby inducing modulation of the envelope of the primary carrier signal for the implanted medical devices. The secondary carrier signal envelopes are modulated based on the measured amplitudes of the respective secondary carrier signals.

Multiple implant communications with adjustable load modulation based on received signal amplitudes

In accordance with the present invention, various embodiments of neurostimulators and stimulation systems are disclosed that provide different shapes and patterns of stimulus pulses and trains of pulses with fixed and no fixed frequencies. The neurostimulator can be configured to provide high frequency stimulation and also be implantable in the head or neck regions in order to stimulate nerves and nerve ganglions in the head and neck regions and also stimulate the brain.

Neurostimulators and stimulation systems

A medical system and method of communicating between a telemetry controller and a plurality of medical devices implanted within a patient is provided. Communication links are respectively established between the telemetry controller and the implanted medical devices. The communication links are respectively amplitude modulated by the implanted medical devices at modulation levels using load modulation. Received signal strength indicators (RSSIs) of the amplitude modulated communication links for the implanted medical devices are measured. A variation of the RSSIs is decreased by modifying, based on the measured RSSIs, at least one modulation level at which the respective at least one communication link is amplitude modulated by the respective implanted medical device(s).

Multiple implant communications with adjustable load modulation using modulation indices

Systems and methods for rectifying and regulating an input voltage are disclosed. A biasing circuit is configured to generate a biasing voltage greater than the maximum value of the input voltage minus a forward bias voltage of a p-n junction diode and apply the biasing voltage to the body terminal of a MOSFET. The biasing circuit may generate the biasing voltage by rectifying the input voltage. A control circuit is configured to generate a gate voltage based on the rectified and regulated output voltage and apply the gate voltage to the gate terminal of the MOSFET.

Rectifier and regulator circuit

A feedback controlled coil driver with ASK modulation is disclosed. A class E coil driver drives an LC circuit to generate a magnetic signal via the inductor. A modulation capacitor is coupled to the LC circuit to modulate the coil driver signal. The voltage across the coil driver switch is sampled. The difference between the sampled voltage and a reference voltage is integrated and compared to a ramp voltage to obtain an optimal on time for the coil driver switch such that coil current is maximized.

Class E coil driver with switched capacitor ASK modulation

A fully integrated feedback controlled coil driver is disclosed for inductive power transfer to electronic devices. For efficient power transfer, a voltage across a switch that switchably couples the coil between a DC input power source and ground is sampled and compared with a preselected reference voltage to generate an error voltage. The error voltage is integrated over time and compared to a voltage ramp. The value of the integrated error voltage relative to the voltage ramp is used to obtain an optimal on time for the switch such that coil current is maximized for a given DC input power. The coil driver can also provide ASK modulation on the coil current by changing the size of the switch according to input data.

Feedback controlled coil driver for inductive power transfer

A timing controlled converter and method for converting a time varying input signal to a regulated DC output voltage for application to a load circuit. A feedback loop is employed as a control means for switchably coupling the time varying input signal to the load circuit for controlled periods of time in a manner so as to provide an average load voltage equal to a reference voltage. The duration of the controlled periods of time is a function of: the difference between the time varying input signal and the output voltage; and the integral of the difference between the output voltage and the reference voltage.

Timing controlled AC to DC converter and method

A successive approximation ADC made of a low voltage configurable differential amplifier and low voltage logic circuits which can convert a high voltage analog input to a digital equivalent. The differential amplifier can be configured as either an op amp or a comparator depending upon the mode of operation. An input capacitor Cis switchably coupled to an electrode selected for voltage sampling. A switched capacitor array Cis coupled across the differential amplifier input and output. A SAR coupled to the switched capacitor array provides a digital output corresponding to the sampled analog voltage. During a sampling interval and a charge transfer interval, the differential amplifier is configured as an op amp. During the transfer interval, the voltage on the input capacitor multiplied by the ratio C/Cis transferred to the switched capacitor array. During an analog to digital conversion interval, the ADC converts the analog voltage to an equivalent digital output.

High voltage monitoring successive approximation analog to digital converter

The various embodiments described herein include systems, methods and/or devices used to produce a rectified and regulated output signal. In one aspect, the method includes, at a circuit, comparing an output signal at an output node with an input signal at an input node, wherein the output signal is a rectified and regulated signal, and the input signal is an unrectified and unregulated signal, and computing a difference between a reference signal and a comparison signal. Power transfer from the input node to the output node is prevented when the output signal is greater than the input signal. Furthermore, power transfer from the input node to the output node is regulated to produce the rectified and regulated output signal when both the input signal is greater than the output signal, and when the magnitude of the reference signal exceeds the magnitude of the comparison signal.

Active rectifier and regulator circuit

A high voltage analog switch operable by a binary signal is implemented in a low voltage semiconductor process. The switch has three parallel circuit paths, with each path comprising at least three series connected transistors. Control signals are selectively applied to the control terminals of the transistors to control the switch and selectively turn on or turn off each of the three circuit paths depending on the input voltage range, so that the breakdown voltage of all of the transistors is never exceeded in any mode of operation.

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Fullerton, CA, United States of America

Edward K F Lee