Abstract: In one embodiment, an implantable pulse generator comprises: pulse generating circuitry for generating pulses and delivering the pulses to outputs of the implantable pulse generator; a controller; wherein the pulse generating circuitry comprises a voltage multiplier for multiplying a battery voltage, the voltage multiplier including multiple outputs, wherein a first output of the multiple outputs provides a voltage that is programmably selectable from a plurality of voltages including non-integer multiples of the battery voltage, wherein a second output of the multiple outputs provides a voltage that is a fixed multiple of the battery voltage; wherein the controller controls the pulse generator circuitry to generate a first pulse for stimulation of the patient using a first output of the multiple outputs and controls the pulse generator circuitry to generate a second pulse to discharge output capacitors of residual charge from the first pulse using a second output of the multiple outputs.

Abstract: Disclosed are systems and methods which provide voltage conversion in increments less than integer multiples of a power supply (e.g., battery) voltage. A representative embodiment provides power supply voltage multipliers in a binary ladder distribution to provide a desired number of output voltage steps using a relatively uncomplicated circuit design. By using different sources in various combinations and/or by “stacking” different sources in various ways, the voltage multiplier circuit may be used to provide desired voltages. In order to minimize the number of components used in a voltage converter of an embodiment, a capacitive voltage converter circuit uses one or more storage capacitors in place of pump capacitors in a voltage generation cycle. Also, certain embodiments do not operate to generate an output voltage until the time that voltage is needed.

Abstract: In one embodiment, an implantable medical device comprises: a rechargeable battery for powering the implantable medical device; an antenna for receiving RF power; and circuitry for charging the rechargeable battery using power received via the antenna, wherein the circuitry for charging comprises control circuitry that causes the circuitry for charging to recharge the rechargeable battery using multiple current levels applied in succession, and wherein the circuitry for charging switches from at least one of the current levels to another current level when a charging voltage of the rechargeable battery reaches a threshold value that is varied by the control circuitry over a lifespan of the rechargeable battery.

Abstract: In one embodiment, a method of operating an implantable pulse generator comprises: providing power to a voltage converter at a first voltage level; outputting a second voltage level by the voltage converter, the second voltage level being a variable voltage level that is controlled by a control signal provided to the voltage converter, the second voltage level being provided to pulse generating circuitry of the implantable pulse generator, the second voltage level being selectable from a plurality of voltages including non-integer multiples of the first voltage level; generating pulses by the pulse generating circuitry, the pulse generating circuitry including current control circuitry for controlling the pulses to cause the pulses to provide substantially constant current to tissue of the patient; and applying at least two different control signals to the voltage converter during individual pulses to provide successively increasing voltages to the pulse generating circuitry during a respective pulse.

Abstract: A low power (and lower cost) implementation for amplifier used in delivering a stimulation pulse is provided according to embodiments through use of a pre-charge period for each pulse. For example, a voltage at a variable output terminal of a digital-to-analog converter is increased on the leading edge of PULSE and INVERTCLK signals to result in an output of an operational amplifier increasing to a predetermined voltage prior to output of a stimulation pulse, according to an embodiment. A shunt path may be implemented to shunt current away from a load during the pre-charge period.

Abstract: To avoid charge accumulation on capacitive connections to implanted electrodes during delivery of stimulation pulses, stimulation pulses are followed by active discharge pulses having opposite polarity of the stimulation pulses. The active discharge pulses preferably have at least one pulse attribute magnitude (e.g., duration, voltage, and/or current) different than a corresponding stimulation pulse and are preferably programmable. Approximately the same total net current flow is delivered during active discharge pulses as during the stimulation pulses, but in the opposite direction and optionally at a lower amplitude. In addition, by reducing the driving voltage and a variable load within the electrical path for delivery of the pulses, power dissipation during active discharge is preferably reduced.

Abstract: In one embodiment, an implantable pulse generator comprises: pulse generating circuitry for generating pulses and delivering the pulses to outputs of the implantable pulse generator; a controller; wherein the pulse generating circuitry comprises a voltage multiplier for multiplying a battery voltage, the voltage multiplier including multiple outputs, wherein a first output of the multiple outputs provides a voltage that is programmably selectable from a plurality of voltages including non-integer multiples of the battery voltage, wherein a second output of the multiple outputs provides a voltage that is a fixed multiple of the battery voltage; wherein the controller controls the pulse generator circuitry to generate a first pulse for stimulation of the patient using a first output of the multiple outputs and controls the pulse generator circuitry to generate a second pulse to discharge output capacitors of residual charge from the first pulse using a second output of the multiple outputs.

Abstract: Embodiments provide a capacitive voltage multiplier for efficiently producing multiples, including fractional multiples, of a power supply voltage use high, medium and low voltage field effect transistors for switching terminals of various capacitors into and out of connection with power supply or ground voltages in charge mode and with an output or other capacitor terminals for series connection in pump mode. A single non-overlapping clock is level-shifted up to the maximum voltage level required for switching to produce a desired output, then level shifted back down to lower levels with delay added as necessary according to embodiments.

Abstract: Disclosed are systems and methods which provide voltage conversion in increments less than integer multiples of a power supply (e.g., battery) voltage. A representative embodiment provides power supply voltage multipliers in a binary ladder distribution to provide a desired number of output voltage steps using a relatively uncomplicated circuit design. By using different sources in various combinations and/or by “stacking” different sources in various ways, the voltage multiplier circuit may be used to provide desired voltages. In order to minimize the number of components used in a voltage converter of an embodiment, a capacitive voltage converter circuit uses one or more storage capacitors in place of pump capacitors in a voltage generation cycle. Also, certain embodiments do not operate to generate an output voltage until the time that voltage is needed.

Abstract: Embodiments provide a capacitive voltage multiplier for efficiently producing multiples, including fractional multiples, of a power supply voltage use high, medium and low voltage field effect transistors for switching terminals of various capacitors into and out of connection with power supply or ground voltages in charge mode and with an output or other capacitor terminals for series connection in pump mode. A single non-overlapping clock is level-shifted up to the maximum voltage level required for switching to produce a desired output, then level shifted back down to lower levels with delay added as necessary according to embodiments.

Abstract: In delivering constant current electrical stimulation pulses to electrodes implanted near a stimulation site, a programmable voltage limited mode of operation according to embodiments precludes unsafe voltage spikes upon substantial changes in resistance due to, for example, patient movement. A voltage multiplier of one embodiment is driven by a clock signal stopped whenever an output voltage reaches a predetermined level, and resumed when the output voltage drops below that level. A comparator receiving a voltage-divided output from the voltage multiplier and a variable input control signal from a digital-to-analog converter controls generation of the clock signal according to embodiments.

Abstract: According to embodiments, amplitude for a stimulation pulse delivered to electrodes implanted within a patient is controlled by a scale circuit and a digital-to-analog converter. The scale circuit selects one of a plurality of overlapping, different sized stimulation pulse amplitude ranges while the digital-to-analog converter selects an amplitude within the selected range. Stimulation pulse amplitude adjustment resolution scales automatically with the selected range, and a lowest range including the desired amplitude is automatically selected.

Abstract: A low power (and lower cost) implementation for amplifier used in delivering a stimulation pulse is provided according to embodiments through use of a pre-charge period for each pulse. For example, a voltage at a variable output terminal of a digital-to-analog converter is increased on the leading edge of PULSE and INVERTCLK signals to result in an output of an operational amplifier increasing to a predetermined voltage prior to output of a stimulation pulse, according to an embodiment. A shunt path may be implemented to shunt current away from a load during the pre-charge period.

Abstract: To avoid charge accumulation on capacitive connections to implanted electrodes during delivery of stimulation pulses, stimulation pulses are followed by active discharge pulses having opposite polarity of the stimulation pulses. The active discharge pulses preferably have at least one pulse attribute magnitude (e.g., duration, voltage, and/or current) different than a corresponding stimulation pulse and are preferably programmable. Approximately the same total net current flow is delivered during active discharge pulses as during the stimulation pulses, but in the opposite direction and optionally at a lower amplitude. In addition, by reducing the driving voltage and a variable load within the electrical path for delivery of the pulses, power dissipation during active discharge is preferably reduced.