Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 C1 is switchably coupled to an electrode selected for voltage sampling. A switched capacitor array C2 is 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 C1/C2 is transferred to the switched capacitor array. During an analog to digital conversion interval, the ADC converts the analog voltage to an equivalent digital output.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 C1 is switchably coupled to an electrode selected for voltage sampling. A switched capacitor array C2 is 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 C1/C2 is transferred to the switched capacitor array. During an analog to digital conversion interval, the ADC converts the analog voltage to an equivalent digital output.

Abstract: A high voltage full wave rectifier and doubler circuit having complementary serially connected low voltage MOSFET stacks to provide high voltage capability. The state of the MOSFETs in the MOSFET stacks is controlled by means of resistors coupled between the circuit's outputs and a time varying input signal. The resistance values of the resistors are selected to maintain operation of the stacked MOSFETs below their breakdown voltages.

Abstract: 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.

Abstract: A timing controlled converter 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.

Abstract: 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.

Abstract: 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 C1 is switchably coupled to an electrode selected for voltage sampling. A switched capacitor array C2 is 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 C1/C2 is transferred to the switched capacitor array. During an analog to digital conversion interval, the ADC converts the analog voltage to an equivalent digital output.

Abstract: An AC-DC step-up converter circuit architecture for generating multiple output voltages, both positive and negative, in an implantable biomedical device is disclosed. Switches and active rectifiers are used inside the converter for charging capacitors from the AC source and delivering currents to the loads. Regulated output voltages with high power efficiency are obtained by controlling the on/off times of the switches using feedback loops that include integrator circuits configured to provide control parameters related to the various output voltages and their associated predetermined reference voltages.

Abstract: Systems and methods for the pulse edge modulation of digital carrier signals for communications systems. A digital carrier signal is generated and the carrier is pulse edge modulated with digital data. A pulse edge modulated signal is generated by either retarding or advancing each pulse edge of a carrier to be modulated relative to its original position in time, depending on the state of the digital bit to be modulated on that edge.

Abstract: Systems and methods for power and bidirectional data transmission using a plurality of wires. A multiphase digital signal is downlinked from a main unit to a remote unit over the plurality of wires and is converted to a DC power signal used to power the remote unit. Uplink data is sent from the remote to the main over one selected wire during a predetermined time period for an uplink transmission by amplitude modulating the received digital signal at the remote. During an uplink, the output impedance of the line driver in the main unit connected to the wire selected for the uplink is increased to allow for the uplink amplitude modulation. The modulated signal is maintained within the noise margins of the digital circuits in the main and remote units.

Abstract: A high voltage full wave rectifier circuit having complementary serially connected low voltage MOSFET stacks provides high voltage rectifier capability. The MOSFET stacks are coupled to a pair of cross coupled MOSFETs that provide a full wave rectified output voltage. The state of the MOSFETs in the MOSFET stacks is controlled by resistors coupled between the rectifier output and a time varying input signal. The resistance values of the resistors are selected to maintain operation of the stacked MOSFETs below their breakdown voltages. A pair of diodes is connected between ground and the MOSFET stacks. A plurality of diode connected MOSFETs are connected between the rectifier output and the resistors to establish bias voltages on the gates of the MOSFETs in the MOSFET stacks to control operation of the rectifier during input voltage cycles. A voltage doubler circuit is also described where low voltage MOSFETs are utilized in a novel configuration to provide high voltage doubling capability.

Abstract: A high voltage current source and a voltage expander implemented in a low voltage semiconductor process. The voltage expander extends the operating voltage range of a stack of transistors to multiple times a supply voltage Vdd at the output node of the stack without exceeding the breakdown voltage of any of the transistors in the stack. The voltage expander uses a diode and a voltage divider to detect the output node voltage changes and generates a plurality of voltages that control the gate voltages for the stack of transistors. A high voltage wide swing current source utilizes a transistor to set the output current and the voltage expander to extend the output voltage range of the current setting transistor. An additional transistor and another current source ensure that the output current is constant throughout the entire output voltage range between about 0V and multiple times the supply voltage Vdd.

Abstract: Systems and methods for power and bidirectional data transmission using a plurality of wires. A multiphase digital signal is downlinked from a main unit to a remote unit over the plurality of wires and is converted to a DC power signal used to power the remote unit. Uplink data is sent from the remote to the main over one selected wire during a predetermined time period for an uplink transmission by amplitude modulating the received digital signal at the remote. During an uplink, the output impedance of the line driver in the main unit connected to the wire selected for the uplink is increased to allow for the uplink amplitude modulation. The modulated signal is maintained within the noise margins of the digital circuits in the main and remote units.

Abstract: A high voltage differential pair and op amp implemented in a low voltage semiconductor process. The high voltage differential pair expands the incoming common mode voltage of a differential pair to multiple times the normal operating voltage of the differential pair through the use of high voltage current sources, current sinks and stacks of transistors. The high voltage op amp includes a high voltage input stage and a high voltage common source amplifier to expand the output voltage range to multiple times the normal operating voltage of the op amp.