EP-4735103-A1 - IMPLANTABLE MEDICAL DEVICE CIRCUITRY INTEGRITY DETECTION

Abstract

An example device includes a hold capacitor configured to store electrical energy for delivery to a patient as a stimulation pulse; one or more charge pump capacitors; a charge circuit coupled to the one or more charge pump capacitors, the charge circuit configured to charge the hold capacitor with electrical energy; a switch positioned between the charge circuit and the hold capacitor; and a charge pump monitor circuit coupled to the charge circuit and configured to monitor charging of the hold capacitor with electrical energy.

Inventors

• ST. MARTIN, JAMES J.
• ANDERSON, Avery M.

Assignees

• Medtronic, Inc.

Dates

Publication Date

20260506

Application Date

20240610

Claims (15)

1. 1. A device comprising: a hold capacitor configured to store electrical energy for delivery to a patient as a stimulation pulse; one or more charge pump capacitors; a charge circuit coupled to the one or more charge pump capacitors, the charge circuit configured to charge the hold capacitor with electrical energy; a switch positioned between the charge circuit and the hold capacitor; and a charge pump monitor circuit coupled to the charge circuit and configured to monitor charging of the hold capacitor with electrical energy.
2. 2. The device recited in claim 1, wherein the charge pump monitor circuit is directly coupled to the charge circuit.
3. 3. The device recited in any of claims 1-2, wherein the charge circuit is configured to perform a charge cycle to charge the hold capacitor.
4. 4. The device recited in claim 3, wherein the charge cycle is from initiating charging of the hold capacitor to when an amplitude of the hold capacitor reaches a particular voltage amplitude threshold.
5. 5. The device recited in any of claims 3-4, wherein the charge pump monitor circuit is configured to determine a duration to perform the charge cycle.
6. 6. The device recited in claim 5, wherein the charge pump monitor circuit is configured to determine the duration to perform the charge cycle based on determining a number of pumps provided by the one or more charge pump capacitors during the charge cycle.
7. 7. The device recited in claim 5, wherein the charge pump monitor circuit is configured to determine the duration to perform the charge cycle based on determining an amount of time of the charge cycle.
8. 8. The device recited in any of claims 5-7, wherein the charge pump monitor circuit is configured to determine whether the duration of the charge cycle satisfies an integrity issue criterion.
9. 9. The device recited in claim 8, wherein, in response to a determination that the duration of the charge cycle satisfies the integrity issue criterion, the charge pump monitor circuit is configured to generate data indicating an integrity issue.
10. 10. The device recited in claim 9, wherein the indicated integrity issue is one or more of an integrity issue of the charge circuit, an integrity issue of the hold capacitor, or an integrity issue of a stimulation pulse delivery path.
11. 11. The device recited in any of claims 1-10, wherein the charge pump monitor circuit is directly coupled to the charge circuit.
12. 12. A device comprising: a memory; and circuitry coupled to the memory, the circuitry configured to: determine a duration of a charge cycle of a hold capacitor configured to store electrical energy for delivery to a patient as a stimulation pulse; determine whether the duration of the charge cycle satisfies an integrity issue criterion; and in response to a determination that the duration of the charge cycle satisfies the integrity issue criterion, generate data indicating an integrity issue.
13. 13. The device recited in claim 12, wherein the indicated integrity issue is one or more of an integrity issue of a charge circuit of the circuitry, an integrity issue of the hold capacitor, or an integrity issue of a stimulation pulse delivery path.
14. 14. The device recited in any of claims 12-13, wherein the processing circuitry is further configured to initiate the charge cycle of the hold capacitor.
15. 15. The device recited in any of claims 12-14, wherein the charge cycle is from initiating charging of the hold capacitor to when an amplitude of the hold capacitor reaches a particular voltage amplitude threshold.

Description

IMPLANTABLE MEDICAL DEVICE CIRCUITRY INTEGRITY DETECTION [0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/510,505, filed June 27, 2023, the entire content of which is incorporated herein by reference. TECHNICAL FIELD [0002] This disclosure relates generally to medical devices and, more particularly, to techniques for evaluating the integrity of implantable medical device circuitry. BACKGROUND [0003] Some types of implantable medical devices (IMDs), such as cardiac pacemakers or implantable cardioverter defibrillators systems, may be used to provide cardiac sensing and therapy for a patient via one or more electrodes. Monitoring performance and integrity of an IMD while using IMD to perform stimulation therapy is important for delivering safe and appropriate therapy. For example, changes to the integrity of circuitry used to deliver electrical stimulation therapy, such as cardiac pacing, may be reflected in changed impedance, and may result in variance of the amplitude or other amount of stimulation delivered to the patient from what was prescribed/intended. SUMMARY [0004] In general, this disclosure is directed to devices, systems, and techniques for determining integrity of one or more of a charge circuit, hold capacitor, and/or stimulation delivery path of an IMD such as a pacemaker or cardioverter defibrillator. In some examples of devices, systems, and techniques described herein, circuitry of an IMD may initiate a counter to determine a duration of a charge cycle to recharge a capacitor, such as a hold capacitor, and generate data, such as an alert, communication, flag, etc., to indicate an integrity issue in one or more of a charge circuit, hold capacitor, and/or stimulation delivery path of an IMD based on whether the duration of the charge cycle satisfies an integrity issue threshold (or other criterion). [0005] In some examples of devices, systems, and techniques described herein, the detection of integrity issues based on determining a duration of charge cycle to recharge a hold capacitor is pace-delivery independent. Determining a duration of a charge cycle of a hold capacitor, while being pace-delivery independent, may help determine satisfaction of an integrity issue criterion without potentially out of specification therapy being applied to a patient. In addition, some examples of devices, systems, and techniques described herein may be able to identify integrity issues while reducing or avoiding use (and consequently a presence in the IMD) of sample capacitors, which may reduce charge lost due to sample capacitors and reduce a risk of short-circuit of a sample capacitor that may lead to inappropriate stimulation therapy delivery. [0006] Some examples of devices, systems, and techniques described herein may help identify isolate and identify a particular charge pump capacitor that has the integrity issue. In some examples, if there is a partial integrity issue within a charge circuit that causes the recharge state to take twice as long to complete, the particular configuration of circuitry described herein may capture this integrity issue without any reprogramming despite the impedance remaining constant. In addition, the particular configuration of circuitry described herein may be sensitive to leakage of a hold capacitor. For example, if a hold capacitor has leakage, impedance would remain constant even if the first sample voltage is lower than expected. The particular configuration of circuitry described herein may determine a duration of a charge cycle of a hold capacitor to determine an increase in recharge time and detect a hold capacitor leakage without any additional hardware. Accordingly, the particular configuration of circuitry described herein is able to determine additional types of integrity issues and/or additional locations of integrity issues. [0007] In one example, the disclosure describes a device comprising a hold capacitor configured to store electrical energy for delivery to a patient as a stimulation pulse; one or more charge pump capacitors; a charge circuit coupled to the one or more charge pump capacitors, the charge circuit configured to charge the hold capacitor with electrical energy; a switch positioned between the charge circuit and the hold capacitor; and a charge pump monitor circuit coupled to the charge circuit and configured to monitor charging of the hold capacitor with electrical energy. [0008] In another example, this disclosure describes a device comprising a memory; and circuitry coupled to the memory, the circuitry configured to: determine a duration of a charge cycle of a hold capacitor configured to store electrical energy for delivery to a patient as a stimulation pulse; determine whether the duration of the charge cycle satisfies an integrity issue criterion; and in response to a determination that the duration of the charge cycle satisfies the integrity issue criterion, generate data indicating an