Sample and Hold Circuitry for Monitoring Voltages in an Implantable Neurostimulator
First Claim
1. Circuitry for an implantable stimulator device, comprising:
- stimulation circuitry comprising a first output and a second output;
a first decoupling capacitor between the first output and a first electrode configured to contact tissue of a patient, and a second decoupling capacitor between the second output and a second electrode configured to contact the tissue of the patient,wherein the stimulation circuitry is configured to provide a stimulation pulse to the first output and the second output to cause current to flow through the first and second decoupling capacitors and through the patient'"'"'s tissue, wherein a parasitic voltage is formed across the first and second decoupling capacitors during the stimulation pulse; and
measurement circuitry configured to receive at least one output voltage at the first output and at least one output voltage at the second output during the stimulation pulse, wherein the measurement circuitry is configured to determine a resistance of the patient'"'"'s tissue using the output voltages, wherein the measurement circuit is further configured to cancel the parasitic voltages from the resistance determination.
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Abstract
Sample and hold circuitry for monitoring electrodes and other voltages in an implantable neurostimulator is disclosed. The sample and hold circuitry in one embodiment contains multiplexers to selected appropriate voltages and to pass them to two storage capacitors during two different measurement phases. The capacitors are in a later stage serially connected to add the two voltages stored on the capacitors, and voltages present at the top and bottom of the serial connection are then input to a differential amplifier to compute their difference. The sample and hold circuitry is particularly useful in calculating the resistance between two electrodes, and is further particularly useful when resistance is measured using a biphasic pulse. The sample and hold circuitry is flexible, and can be used to measure other voltages of interest during biphasic or monophasic pulsing.
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Citations
20 Claims
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1. Circuitry for an implantable stimulator device, comprising:
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stimulation circuitry comprising a first output and a second output; a first decoupling capacitor between the first output and a first electrode configured to contact tissue of a patient, and a second decoupling capacitor between the second output and a second electrode configured to contact the tissue of the patient, wherein the stimulation circuitry is configured to provide a stimulation pulse to the first output and the second output to cause current to flow through the first and second decoupling capacitors and through the patient'"'"'s tissue, wherein a parasitic voltage is formed across the first and second decoupling capacitors during the stimulation pulse; and measurement circuitry configured to receive at least one output voltage at the first output and at least one output voltage at the second output during the stimulation pulse, wherein the measurement circuitry is configured to determine a resistance of the patient'"'"'s tissue using the output voltages, wherein the measurement circuit is further configured to cancel the parasitic voltages from the resistance determination. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. Circuitry for an implantable stimulator device, comprising:
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stimulation circuitry configured to provide a first stimulation pulse with a first pulse phase and a second pulse phase from a first output to a first electrode configured to contact tissue of a patient, and to simultaneously provide a second stimulation pulse with a first pulse phase and a second pulse phase from a second output to a second electrode configured to contact tissue of the patient; a first capacitor between the first output and the first electrode, and a second capacitor between the second output and the second electrode, wherein first and second parasitic voltages are respectively formed across the first and second capacitors during the first and second pulse phases; and measurement circuitry configured to receive a first output voltage at the first output and a second output voltage at the second output during both of the first and second pulse phases, wherein the measurement circuitry is configured to determine a resistance of the patient'"'"'s tissue using the received first and second output voltages, wherein the measurement circuit is further configured to cancel the first and second parasitic voltages from the resistance determination. - View Dependent Claims (18, 19, 20)
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Specification