Abstract: Waveforms for a stimulator device, and methods and circuitry for generating them, are disclosed having high- and low-frequency aspects. The waveforms comprise a sequence of pulses issued at a low frequency which each pulse comprising first and second charge-balanced phases. One or both of the phases comprises a plurality a monophasic sub-phase pulses issued at a high frequency in which the sub-phase pulses are separated by gaps. The current during the gaps in a phase can be zero, or can comprise a non-zero current of the same polarity as the sub-phase pulses issued during that phase. The disclosed waveforms provide benefits of high frequency stimulation such as the promotion of paresthesia free, sub-threshold stimulation, but without drawbacks inherent in using high-frequency biphasic pulses.

Abstract: Recognizing that anodic stimulation may require higher amplitudes or charge than cathodic stimulation in some tissues, new pulsing waveforms for a stimulator device, and particularly useful during monopolar stimulation, are described employing therapeutically-effective anodic and cathodic stimulation pulses at the lead-based electrode(s). The pulses are monophasic, with the amplitude or charge of the anodic monophasic pulses being higher than the cathodic monophasic pulses. To provide charge balance at each electrode, a pulse packet may be defined having a plurality of cathodic monophasic pulses and perhaps only a single anodic monophasic pulse. Because the polarity of cathodic monophasic pulses in each packet may charge balance with the anodic monophasic pulse(s), active charge recovery such as by the use of biphasic pulses may not be necessary, although passive charge recovery can be used if desired.

Abstract: This document discusses, among other things, systems and methods for programming neuromodulation therapy to treat neurological or cardiovascular diseases. A system includes an input circuit that receives a modulation magnitude representing a level of stimulation intensity, a memory that stores a plurality of gain functions associated with a plurality of modulation parameters, and a electrostimulator that may generate and deliver an electrostimulation therapy. A controller may program the electrostimulator with the plurality of modulation parameters based on the received modulation magnitude and the plurality of gain functions, and control the electrostimulator to generate electrostimulation therapy according to the plurality of modulation parameters.

Abstract: Passive tissue biasing circuitry in an Implantable Pulse Generator (IPG) is disclosed to facilitate the sensing of neural responses by holding the voltage of the tissue to a common mode voltage (Vcm). The IPG's conductive case electrode, or any other electrode, is passively biased to Vcm using a capacitor, as opposed to actively driving the (case) electrode to a prescribed voltage using a voltage source. Once Vcm is established, voltages accompanying the production of stimulation pulses will be referenced to Vcm, which eases neural response sensing. An amplifier can be used to set a virtual reference voltage and to limit the amount of current that flows to the case during the production of Vcm. In other examples, circuitry can be used to monitor the virtual reference voltage as useful to enabling the sensing the neural responses, and as useful to setting a compliance voltage for the current generation circuitry.

Abstract: Timing channel circuitry for controlling stimulation circuitry in an implantable stimulator is disclosed. The timing channel circuitry comprises a addressable memory. Data for the various phases of a desired pulse are stored in the memory using different numbers of words, including a command indicative of the number of words in the phase, a next address for the next phase stored in the memory, and a pulse width or duration of the current phase, control data for the stimulation circuitry, pulse amplitude, and electrode data. The command data is used to address through the words in the current phase via the address bus, which words are sent to a control register for the stimulation circuitry. After the duration of the pulse width for the current phase has passed, the stored next address is used to access the data for the next phase stored in the memory.

Abstract: Methods, devices and systems for developing new therapy options for patient suffering from neurological disorders. An example may include the use of a therapy patterning system that allows significant freedom to program therapy patterns using arbitrary shapes and functions. For such patterning to be implemented, a physician may identify a condition needing new and/or alternative therapy options, link the identified condition one or more therapy parameters, program, test and assess the therapy. The process may include multiple iterations to address an initial condition and then to mitigate side effects of the initial therapy. Some embodiments comprises devices configured to deliver combinations of therapy patterns to accomplish at least first and second therapeutic purposes.

Abstract: Circuitry for generating a compliance voltage (V+) for the current sources and/or sinks in an implantable stimulator device in disclosed. The circuitry assesses whether V+ is optimal for a given pulse, and if not, adjusts V+ for the next pulse. The circuitry uses amplifiers to measure the voltage drop across active PDACs (current sources) and NDAC (current sinks) at an appropriate time during the pulse. The measured voltages are assessed to determine whether they are high or low relative to optimal values. If low, a V+ regulator is controlled to increase V+ for the next pulse; if not, the V+ regulator is controlled to decrease V+ for the next pulse. Through this approach, gradual changes that may be occurring in the implant environment can be accounted for, with V+ adjusted on a pulse-by-pulse basis to keep the voltage drops at or near optimal levels for efficient DAC operation.

Abstract: A therapeutic neuromodulation system configured for providing therapy to a patient. The therapeutic neuromodulation system comprises a plurality of electrical terminals configured for being respectively coupled to a plurality of electrodes implanted within tissue, analog output circuitry configured for delivering therapeutic electrical energy between the plurality of electrical terminals in accordance with a set of modulation parameters that includes a defined current value, a voltage regulator configured for supplying an adjustable compliance voltage to the analog output circuitry, and control/processing circuitry configured for automatically performing a compliance voltage calibration process at a compliance voltage adjustment interval by periodically computing an adjusted compliance voltage value as a function of a compliance voltage margin.

Abstract: Temperature sensing circuitry for an Implantable Medical Device (IMD) is disclosed that can be integrated into integrated circuitry in the IMD and draws very little power, thus enabling continuous temperature monitoring without undue battery depletion. Temperature sensor and threshold setting circuitry produces analog voltage signals indicative of a sensed temperature and at least one temperature threshold. Such circuitry employs a Ptat current reference stage and additional stages, which stages contains resistances that are set based on the desired temperature threshold(s) and to set the voltage range of the sensed temperature. These analog voltages are received at temperature threshold detection circuitry, which produces digital signal(s) indicating whether the sensed temperature has passed the temperature threshold(s). The digital signal(s) are then provided to digital circuitry in the IMD, where they can be stored as a function of time for later review, or used to immediately to control IMD operation.

Abstract: A therapeutic neuromodulation system configured for providing therapy to a patient. The therapeutic neuromodulation system comprises a plurality of electrical terminals configured for being respectively coupled to a plurality of electrodes implanted within tissue, analog output circuitry configured for delivering therapeutic electrical energy between the plurality of electrical terminals in accordance with a set of modulation parameters that includes a defined current value, a voltage regulator configured for supplying an adjustable compliance voltage to the analog output circuitry, and control/processing circuitry configured for automatically performing a compliance voltage calibration process at a compliance voltage adjustment interval by periodically computing an adjusted compliance voltage value as a function of a compliance voltage margin.

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 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: The disclosed techniques allow for externalizing errors from an implantable medical device using the device's charging coil, for receipt at an external charger or other external device. Transmission of errors in this manner is particularly useful when telemetry of error codes through a traditional telemetry coil in the implant is not possible, for example, because the error experienced is so fundamental as to preclude use of such traditional means. By externalizing the error via the charging coil, and though the use of robust error modulation circuitry in the implant designed to be generally insensitive to fundamental errors, the external charger can be consulted to understand the failure mode involved, and to take appropriate action.

Abstract: The disclosed techniques allow for externalizing errors from an implantable medical device using the device's charging coil, for receipt at an external charger or other external device. Transmission of errors in this manner is particularly useful when telemetry of error codes through a traditional telemetry coil in the implant is not possible, for example, because the error experienced is so fundamental as to preclude use of such traditional means. By externalizing the error via the charging coil, and though the use of robust error modulation circuitry in the implant designed to be generally insensitive to fundamental errors, the external charger can be consulted to understand the failure mode involved, and to take appropriate action.

Abstract: Temperature sensing circuitry for an Implantable Medical Device (IMD) is disclosed that can be integrated into integrated circuitry in the IMD and draws very little power, thus enabling continuous temperature monitoring without undue battery depletion. Temperature sensor and threshold setting circuitry produces analog voltage signals indicative of a sensed temperature and at least one temperature threshold. Such circuitry employs a Ptat current reference stage and additional stages, which stages contains resistances that are set based on the desired temperature threshold(s) and to set the voltage range of the sensed temperature. These analog voltages are received at temperature threshold detection circuitry, which produces digital signal(s) indicating whether the sensed temperature has passed the temperature threshold(s). The digital signal(s) are then provided to digital circuitry in the IMD, where they can be stored as a function of time for later review, or used to immediately to control IMD operation.

Abstract: Charging circuitry is disclosed for receiving a magnetic charging field and using the received field to charge a battery in an Implantable Medical Device (IMD) without passive trickle charging, and even if the battery voltage (Vbat) is severely depleted. The charging circuitry includes a source capable of producing a constant charging current via a current mirror that receives a reference current for setting the charging current. Two reference current generators are provided: a first enabled when Vbat is severely depleted to produce a small non-adjustable reference current; and a second enabled once Vbat is recovered to produce a reference current that can be controlled to adjust the charging current. Because Vbat may be too low, the first generator is powered by a DC voltage produced from the magnetic charging field. A passively-generated undervoltage control signal is used to transition between use of the first and second generators.

Abstract: Timing channel circuitry for controlling stimulation circuitry in an implantable stimulator is disclosed. The timing channel circuitry comprises a addressable memory. Data for the various phases of a desired pulse are stored in the memory using different numbers of words, including a command indicative of the number of words in the phase, a next address for the next phase stored in the memory, and a pulse width or duration of the current phase, control data for the stimulation circuitry, pulse amplitude, and electrode data. The command data is used to address through the words in the current phase via the address bus, which words are sent to a control register for the stimulation circuitry. After the duration of the pulse width for the current phase has passed, the stored next address is used to access the data for the next phase stored in the memory.

Abstract: An algorithm programmed into the control circuitry of a rechargeable-battery Implantable Medical Device (IMD) is disclosed that can quantitatively forecast and determine the timing of an early replacement indicator (tEOLi) and an IMD End of Life (tEOL). These forecasts and determinations of tEOLi and tEOL occur in accordance with one or more parameters having an effect on rechargeable battery capacity, such as number of charging cycles, charging current, discharge depth, load current, and battery calendar age. The algorithm consults such parameters as stored over the history of the operation of the IMD in a parameter log, and in conjunction with a battery capacity database reflective of the effect of these parameters on battery capacity, determines and forecasts tEOLi and tEOL. Such forecasted or determined values may also be used by a shutdown algorithm to suspend therapeutic operation of the IMD.

Abstract: The problem of a potentially high amount of supra-threshold charge passing through the patient's tissue at the end of an Implantable Pulse Generator (IPG) program is addressed by circuitry that periodically dissipates only small amount of the charge stored on capacitances (e.g., DC-blocking capacitors) during a pulsed post-program recovery period. This occurs by periodically activating control signals to turn on passive recovery switches to form a series of discharge pulses each dissipating a sub-threshold amount of charge. Such periodic pulsed dissipation may extend the duration of post-program recovery, but is not likely to be noticeable by the patient when the programming in the IPG changes from a first to a second program. Periodic pulsed dissipation of charge may also be used during a program, such as between stimulation pulses.