# US 2023/0264014 A1 · Sensing evoked compound action potential (ecap) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0264014 A1 - Document ID: US20230264014A1 - Status: Published application - Kind: A1 - Application number: 18/161,499 - Filed: 2023-01-30 - Published: 2023-08-24 - Earliest claimed: 2022-02-21 - Assignees: Medtronic, Inc. - Applicants: Medtronic, Inc. - Inventors: Robert A. Corey; Joel A. Anderson; David A. Dinsmoor; Kristin N. Hageman; Scott R. Stanslaski; Todd V. Smith; Heba Tareq Omar - Web page: https://patentgrep.com/patent/US20230264014A1 ## CPC - A61N 1/025: {Digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors} - A61N 1/36139: {with automatic adjustment} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract A system for providing therapy to a patient includes stimulation generation circuitry, sensing circuitry, and processing circuitry. The processing circuitry is configured to cause storage of a first voltage at a first terminal at a first calibration capacitor and storage of a second voltage at a second terminal at a second calibration capacitor. The processing circuitry is configured to switch out a first calibration switch to prevent the first voltage stored at the first calibration capacitor from changing and switch out a second calibration switch to prevent the second voltage stored at the second calibration capacitor from changing and determine, with the sensing circuitry, a sensing signal based on the first voltage offset by a first calibration voltage stored by the first capacitor and based on the second voltage offset by a second calibration voltage stored by the second capacitor. ## Claims ### Claim 1 A system for providing therapy to a patient, the system comprising: stimulation generation circuitry configured to provide electrical stimulation to the patient; sensing circuitry configured to sense a first voltage at a first terminal and to sense a second voltage at a second terminal; and processing circuitry electrically connected to the sensing circuitry and the stimulation generation circuitry, the processing circuitry being configured to: when the stimulation generation circuitry does not provide the electrical stimulation, cause storage of the first voltage at the first terminal at a first calibration capacitor and storage of the second voltage at the second terminal at a second calibration capacitor; after the first voltage is stored at the first calibration capacitor and the second voltage is stored at the second calibration capacitor and when the stimulation generation circuitry provides the electrical stimulation, switch out a first calibration switch to prevent the first voltage stored at the first calibration capacitor from changing and switch out a second calibration switch to prevent the second voltage stored at the second calibration capacitor from changing; while the first calibration switch is switched out and the second calibration switch is switched out and when the stimulation generation circuitry does not provide the electrical stimulation, determine, with the sensing circuitry, a sensing signal based on the first voltage at the first terminal offset by a first calibration voltage stored by the first capacitor and based on the second voltage at the second terminal offset by a second calibration voltage stored by the second capacitor; and cause the stimulation generation circuitry to deliver the therapy to the patient based on the sensing signal. ### Claim 2 (depends on 1) The system of claim 1, further comprising amplifier circuitry configured to: receive the sensing signal; amplify, using a first stage amplifier and at least a second stage amplifier, the sensing signal to generate an amplified sensing signal; and wherein the processing circuitry is configured to cause the stimulation generation circuitry to deliver the therapy based on the amplified sensing signal. ### Claim 3 (depends on 2) The system of claim 2, wherein to amplify, the first stage amplifier amplifies the sensing signal to a first amplified sensing signal for output to the second stage amplifier and wherein the amplifier circuitry further comprises a set of blanking switches configured to: when the stimulation generation circuitry provides the electrical stimulation, block the first amplified sensing signal from being received at an input of the second stage amplifier; and when the stimulation generation circuitry does not provide the electrical stimulation, allow the first amplified sensing signal to be received at the input of the second stage amplifier. ### Claim 4 (depends on 3) The system of claim 3, further comprising a set of switches configured to: when the stimulation generation circuitry provides the electrical stimulation, block the sensing signal from being received at an input of the first stage amplifier; and when the stimulation generation circuitry does not provide the electrical stimulation, allow the first amplified sensing signal to be received at the input of the first stage amplifier. ### Claim 5 (depends on 4) The system of claim 4, wherein, to block the sensing signal from being received at the input of the first stage amplifier, the set of switches is configured to block the sensing signal after a first time delay from when the stimulation generation circuitry no longer provides the electrical stimulation; and wherein, to block the first amplified sensing signal from being received at the input of the second stage amplifier, the set of blanking switches is configured to block the sensing signal after a second time delay from when the stimulation generation circuitry no longer provides the electrical stimulation, wherein the second time delay is different from the first time delay. ### Claim 6 (depends on 5) The system of claim 5, wherein the second time delay is longer than the first time delay. ### Claim 7 (depends on 3) The system of claim 3, further comprising a set of blanking switches configured to clamp a voltage of the sensing signal to a threshold voltage range. ### Claim 8 (depends on 7) The system of claim 7, wherein the threshold voltage range comprises a component safe voltage range. ### Claim 9 (depends on 2) The system of claim 2, wherein the first stage amplifier comprises a transconductance amplifier. ### Claim 10 (depends on 2) The system of claim 2, wherein the second amplifier stage is configured to auto-zero at input and comprises a direct transconductance amplifier. ### Claim 11 (depends on 10) The system of claim 10, wherein the amplifier circuitry comprises a third amplifier stage configured to receive an output of the second amplifier stage and to auto-zero at input, wherein the third amplifier stage comprises a linearized transconductance amplifier. ### Claim 12 (depends on 11) The system of claim 11, wherein the amplifier circuitry comprises a fourth amplifier stage configured to receive an output of the third amplifier stage and to auto-zero at input. ### Claim 13 (depends on 9) The system of claim 9, wherein the processing circuitry is further configured to: when the stimulation generation circuitry provides the electrical stimulation, block the first amplified sensing signal from being received at an input of the second stage amplifier; and when the stimulation generation circuitry does not provide the electrical stimulation, allow the first amplified sensing signal to be received at the input of the second stage amplifier. ### Claim 14 (depends on 2) The system of claim 2, further comprising injection circuitry configured to inject a cancelling offset between the first stage amplifier and the second stage of amplifier. ### Claim 15 (depends on 14) The system of claim 14, wherein the injection circuitry is further configured to generate the cancelling offset based on a weighted set of digital historical offsets of waveforms. ### Claim 16 (depends on 15) The system of claim 15, wherein the processing circuitry is configured to determine the weighted set of digital historical offsets of waveforms based on one or more previous sensing signals that occur before the sensing signal. ### Claim 17 (depends on 15) The system of claim 15, wherein the injection circuitry is further configured to generate the cancelling offset by applying an integral controller on the weighted set of digital historical offsets of waveforms. ### Claim 18 (depends on 1) The system of claim 1, wherein the processing circuitry is configured to: generate a waveform based on the sensing signal; perform a derivative operation on the waveform; after performing the derivative operation, apply a peak minus trough operation to the waveform to determine an amplitude value; and cause the stimulation generation circuitry to deliver the therapy based on the amplitude value. ### Claim 19 A method comprising: when stimulation generation circuitry does not provide the electrical stimulation, causing, by processing circuitry, storage of a first voltage at a first terminal of sensing circuitry at a first calibration capacitor and causing, by the processing circuitry, storage of a second voltage at a second terminal of the sensing circuitry at a second calibration capacitor; after causing the storage of the first voltage at the first calibration capacitor and causing the storage of the second voltage at the second calibration capacitor and when the stimulation generation circuitry provides the electrical stimulation, switching out, by the processing circuitry, a first calibration switch to prevent the first voltage stored at the first calibration capacitor from changing and switching out, by the processing circuitry, a second calibration switch to prevent the second voltage stored at the second calibration capacitor from changing; while the first calibration switch is switched out and the second calibration switch is switched out and when the stimulation generation circuitry does not provide the electrical stimulation, determining, by the processing circuitry, a sensing signal based on the first voltage at the first terminal offset by a first calibration voltage stored by the first capacitor and based on the second voltage at the second terminal offset by a second calibration voltage stored by the second capacitor; and causing, by the processing circuitry, the stimulation generation circuitry to deliver the therapy to the patient based on the sensing signal. ### Claim 20 A medical device comprising: stimulation generation circuitry configured to provide electrical stimulation to the patient; sensing circuitry configured to sense a first voltage at a first terminal and to sense a second voltage at a second terminal; and processing circuitry electrically connected to the sensing circuitry and the stimulation generation circuitry, the processing circuitry being configured to: when the stimulation generation circuitry does not provide the electrical stimulation, cause storage of the first voltage at the first terminal at a first calibration capacitor and cause storage of the second voltage at the second terminal at a second calibration capacitor; after the first voltage is stored at the first calibration capacitor and the second voltage is stored at the second calibration capacitor and when the stimulation generation circuitry provides the electrical stimulation, switch out a first calibration switch to prevent the first voltage stored at the first calibration capacitor from changing and switch out a second calibration switch to prevent the second voltage stored at the second calibration capacitor from changing; while the first calibration switch is switched out and the second calibration switch is switched out and when the stimulation generation circuitry does not provide the electrical stimulation, determine, with the sensing circuitry, a sensing signal based on the first voltage at the first terminal offset by a first calibration voltage stored by the first capacitor and based on second voltage at the second terminal offset by a second calibration voltage stored by the second capacitor; and cause the stimulation generation circuitry to deliver the therapy to the patient based on the sensing signal.