Abstract: Digital-to-Analog (DAC) circuitry for an implantable pulse generator is disclosed which is used to program currents at the electrodes. Calibration circuitry allows the positive and negative currents produced at each electrode to be independently calibrated to achieve an ideal (linear) response across a range of amplitude values provided to the DAC circuitry by a digital amplitude bus. The calibration circuitry includes electrode gain and electrode offset circuitry for each of the electrodes. Current range DAC circuitry is also provided which can be used to adjust the gain and offset current at all of the electrodes. The current range DAC circuitry is particularly useful when spanning a range of therapeutic currents for a patient, and allows all possible amplitude values provided by the digital bus to be used to span the range. This can improve (reduce) the current resolution of the electrode currents with each amplitude value step.

Abstract: An implantable pulse generator (IPG) is disclosed having an improved ability to steer anodic and cathodic currents between the IPG's electrodes. Each electrode node has at least one PDAC/NDAC pair to source/sink or sink/source a stimulation current to an associated electrode node. Each PDAC and NDAC receives a current with a magnitude indicative of a total anodic and cathodic current, and data indicative of a percentage of that total that each PDAC and NDAC will produce in the patient's tissue at any given time, which activates a number of branches in each PDAC or NDAC. Each PDAC and NDAC may also receive one or more resolution control signals specifying an increment by which the stimulation current may be adjusted at each electrode. The current received by each PDAC and NDAC is generated by a master DAC, and is preferably distributed to the PDACs and NDACs by distribution circuitry.

Abstract: An implantable pulse generator (IPG) is disclosed having an improved ability to steer anodic and cathodic currents between the IPG's electrodes. Each electrode node has at least one PDAC/NDAC pair to source/sink or sink/source a stimulation current to an associated electrode node. Each PDAC and NDAC receives a current with a magnitude indicative of a total anodic and cathodic current, and data indicative of a percentage of that total that each PDAC and NDAC will produce in the patient's tissue at any given time, which activates a number of branches in each PDAC or NDAC. Each PDAC and NDAC may also receive one or more resolution control signals specifying an increment by which the stimulation current may be adjusted at each electrode. The current received by each PDAC and NDAC is generated by a master DAC, and is preferably distributed to the PDACs and NDACs by distribution circuitry.

Abstract: An optimization algorithm is disclosed for optimizing an implantable pulse generator. The algorithm is particularly useful when one or more of the electrodes (e.g., the case electrode) is used to provide a common mode voltage (Vcm) to the tissue, which assists in sensing neural responses to the stimulation. The algorithm preferably optimizes both the compliance voltage VH used to power the simulation circuitry, and the strength of tissue driver circuitry used to provide Vcm to the tissue. The algorithm preferably considers information determined by VH measurement circuitry (which informs as to the ability to form prescribed stimulation pulses without loading), sensing monitoring circuitry (which informs as to the magnitude of the inputs of the sensing circuitry), and/or tissue monitoring circuitry (which informs as to adequacy of the strength of the tissue driver circuitry).

Abstract: Sense amplifier circuits particularly useful in sensing neural responses in an Implantable Pulse Generator (IPG) are disclosed. The IPG includes a plurality of electrodes, with one selected as a sensing electrode and another selected as a reference to differentially sense the neural response in a manner that subtracts a common mode voltage (e.g., stimulation artifact) from the measurement. The circuits include a differential amplifier which receives the selected electrodes at its inputs, and comparator circuitries to assess each differential amplifier input to determine whether it is of a magnitude that is consistent with the differential amplifier's input requirements. Based on these determinations, an enable signal is generated which informs whether the output of the differential amplifier validly provides the neural response at any point in time.

Abstract: An implantable pulse generator (IPG) is disclosed having an improved ability to steer anodic and cathodic currents between the IPG's electrodes. Each electrode node has at least one PDAC/NDAC pair to source/sink or sink/source a stimulation current to an associated electrode node. Each PDAC and NDAC receives a current with a magnitude indicative of a total anodic and cathodic current, and data indicative of a percentage of that total that each PDAC and NDAC will produce in the patient's tissue at any given time, which activates a number of branches in each PDAC or NDAC. Each PDAC and NDAC may also receive one or more resolution control signals specifying an increment by which the stimulation current may be adjusted at each electrode. The current received by each PDAC and NDAC is generated by a master DAC, and is preferably distributed to the PDACs and NDACs by distribution circuitry.

Abstract: An implantable pulse generator (IPG) is disclosed having a plurality of electrode nodes, each electrode node configured to be coupled to an electrode to provide stimulation pulses to a patient's tissue. The IPG includes a digital-to-analog converter configured to amplify a reference current to a first current specified by first control signals; a first resistance configured to receive the first current, wherein a voltage across the first resistance is held to a reference voltage at a first node; a plurality of branches each comprising a second resistance and configured to produce a branch current, wherein a voltage across each second resistance is held to the reference voltage at second nodes; and a switch matrix configurable to selectively couple any branch current to any of the electrode nodes via the second nodes.

Abstract: Sense amplifier (amp) circuitry for an implantable stimulator device is disclosed useful for sensing neural responses or other voltages in a patient's tissue. The sense amp circuitry comprises a low-voltage and a high-voltage sense amp circuit, either of which may be selected based on an assessment of the magnitude of the voltage at either or both of the inputs connected to selected sensing electrodes. The assessed magnitude, as determined by monitoring circuitry, can be processed by an algorithm to select use of one of the sense amp circuits, selecting the low-voltage sense amp circuit when the magnitude(s) are lower, and the high-voltage sense amp circuit when the magnitude(s) are higher. Furthermore, DC offset compensation circuitry is disclosed to equate the DC levels of the inputs, which may only operate when the high-voltage sense amp is selected.

Abstract: Improved stimulation circuitry for controlling the stimulation delivered by an implantable stimulator is disclosed. The stimulation circuitry includes memory circuitry that stores pulse programs that define pulse shapes, steering programs that define electrode configurations, and aggregate programs that link a selected pulse program with a selected steering program. The aggregate programs also include an amplitude modulation factor that modulates the amplitude defined by the pulse program. The inclusion of an amplitude modulation factor in the aggregate program allows complex amplitude-modulated waveforms to be produced. Pulse definition circuits in the stimulation circuitry execute aggregate programs to generate stimulation waveforms, which stimulation waveforms can be generated simultaneously by the different pulse definition circuits.

Abstract: Sense amplifier circuits particularly useful in sensing neural responses in an Implantable Pulse Generator (IPG) are disclosed. The IPG includes a plurality of electrodes, with one selected as a sensing electrode and another selected as a reference to differentially sense the neural response in a manner that subtracts a common mode voltage (e.g., stimulation artifact) from the measurement. The circuits include a differential amplifier which receives the selected electrodes at its inputs, and comparator circuitries to assess each differential amplifier input to determine whether it is of a magnitude that is consistent with the differential amplifier's input requirements. Based on these determinations, an enable signal is generated which informs whether the output of the differential amplifier validly provides the neural response at any point in time.

Abstract: Regulator circuitry for producing a regulated output voltage in an implantable stimulation device and associated methods are disclosed. The regulator circuitry is particularly useful where a load current drawn from the output voltage involves transients, such as occurs when the output voltage is used to power a charge pump that creates a higher power supply voltage (e.g., a compliance voltage) in the device. The output current is sampled and downscaled in the regulator, and is further mirrored and filtered. This filtered current provides a control voltage in which transients are minimized and smoothed, and which is more suitable for use as a feedback voltage when producing the output voltage.

Abstract: Methods and circuitry for calibrating stimulation circuitry in an implantable stimulator device (ISD) is disclosed. The ISD can sense neural response to the stimulation, and use an algorithm to assess those responses and determine a therapeutic window for a particular stimulation parameter, such as amplitude. Stimulation circuitry in the ISD is programmed with information indicative of the determined therapeutic window, such as by programming a minimum and/or maximum current amplitude. As well as restricting operation of the stimulation circuitry to within the therapeutic amplitude window, such programming calibrates the stimulation circuitry and allows an expanded range of, or all of, amplitude values supported by the stimulation circuitry to be used, which allows the amplitude to be incremented in smaller current increments.

Abstract: An implantable pulse generator (IPG) is disclosed having a plurality of electrode nodes, each electrode node configured to be coupled to an electrode to provide stimulation pulses to a patient's tissue. The IPG includes a digital-to-analog converter configured to amplify a reference current to a first current specified by first control signals; a first resistance configured to receive the first current, wherein a voltage across the first resistance is held to a reference voltage at a first node; a plurality of branches each comprising a second resistance and configured to produce a branch current, wherein a voltage across each second resistance is held to the reference voltage at second nodes; and a switch matrix configurable to selectively couple any branch current to any of the electrode nodes via the second nodes.

Abstract: Improved stimulation circuitry for controlling the stimulation delivered by an implantable stimulator is disclosed. The stimulation circuitry includes memory circuitry that stores pulse programs that define pulse shapes, steering programs that define electrode configurations, and aggregate programs that link a selected pulse program with a selected steering program. The aggregate programs also include an amplitude modulation factor that modulates the amplitude defined by the pulse program. The inclusion of an amplitude modulation factor in the aggregate program allows complex amplitude-modulated waveforms to be produced. Pulse definition circuits in the stimulation circuitry execute aggregate programs to generate stimulation waveforms, which stimulation waveforms can be generated simultaneously by the different pulse definition circuits.

Abstract: An electrical stimulation system includes at least one electrical stimulation lead having stimulation electrodes; and a processor coupled to the at least one electrical stimulation lead to perform actions, including: directing delivery of at least one stimulation pulse to tissue of a patient during each charge injection phase, where each consecutive pair of the charge injection phases is separated by a charge recovery phase; and, for at least one stimulation pulse: during delivery of the stimulation pulse, directing application of at least one charge recovery pulse to interrupt the delivery of the stimulation pulse, where each one of the at least one charge recovery pulse has a relative amplitude that is larger in magnitude than an amplitude of the stimulation pulse; and, after application of the charge recovery pulse, directing resumption of delivery of the stimulation pulse at the amplitude of the stimulation pulse.

Abstract: Digital-to-Analog (DAC) circuitry for an implantable pulse generator is disclosed which is used to program currents at the electrodes. Calibration circuitry allows the positive and negative currents produced at each electrode to be independently calibrated to achieve an ideal (linear) response across a range of amplitude values provided to the DAC circuitry by a digital amplitude bus. The calibration circuitry includes electrode gain and electrode offset circuitry for each of the electrodes. Current range DAC circuitry is also provided which can be used to adjust the gain and offset current at all of the electrodes. The current range DAC circuitry is particularly useful when spanning a range of therapeutic currents for a patient, and allows all possible amplitude values provided by the digital bus to be used to span the range. This can improve (reduce) the current resolution of the electrode currents with each amplitude value step.

Abstract: An Implantable Pulse Generator (IPG) or External Trial Stimulator (ETS) system is disclosed that is capable of sensing an Evoked Compound Action Potential (ECAP), and (perhaps in conjunction with an external device) is capable of adjusting a stimulation program while keeping a location of a Central Point of Stimulation (CPS) constant. Specifically, one or more features of measured ECAP(s) indicative of its shape and size are determined, and compared to thresholds or ranges to modify the electrode configuration of the stimulation program.

Abstract: An Implantable Pulse Generator (IPG) or External Trial Stimulator (ETS) system is disclosed that is capable of sensing an Evoked Compound Action Potential (ECAP), and (perhaps in conjunction with an external device) is capable of adjusting a stimulation program while keeping a location of a Central Point of Stimulation (CPS) constant. Specifically, one or more features of measured ECAP(s) indicative of its shape and size are determined, and compared to thresholds or ranges to modify the electrode configuration of the stimulation program.

Abstract: An implantable pulse generator (IPG) is disclosed having a plurality of electrode nodes, each electrode node configured to be coupled to an electrode to provide stimulation pulses to a patient's tissue. The IPG includes a digital-to-analog converter configured to amplify a reference current to a first current specified by first control signals; a first resistance configured to receive the first current, wherein a voltage across the first resistance is held to a reference voltage at a first node; a plurality of branches each comprising a second resistance and configured to produce a branch current, wherein a voltage across each second resistance is held to the reference voltage at second nodes; and a switch matrix configurable to selectively couple any branch current to any of the electrode nodes via the second nodes.

Abstract: An implantable pulse generator (IPG) is disclosed having a plurality of electrode nodes, each electrode node configured to be coupled to an electrode to provide stimulation pulses to a patient's tissue. The IPG includes a digital-to-analog converter configured to amplify a reference current to a first current specified by first control signals; a first resistance configured to receive the first current, wherein a voltage across the first resistance is held to a reference voltage at a first node; a plurality of branches each comprising a second resistance and configured to produce a branch current, wherein a voltage across each second resistance is held to the reference voltage at second nodes; and a switch matrix configurable to selectively couple any branch current to any of the electrode nodes via the second nodes.