Detection of possible failure of capacitive elements in an implantable medical device

• US 20030204225A1
• Filed: 04/26/2002
• Published: 10/30/2003
• Est. Priority Date: 04/26/2002
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Torgerson, Nathan A., Stein, Marc, Heathershaw, Todd D.
• Granted Patent: US 7,089,057 B2
• Time in Patent Office: Days
• US Class Current: 607/48
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components

Abstract

Apparatus and method for monitoring capacitive elements of an implantable medical device system for device failure and responding thereto. A therapy measurement block monitors a charge value across one or more capacitive elements. If the charge value falls outside a prescribed range, indicating possible failure in the capacitive element, the system removes from service the capacitive element and its associated regulator, notifies the implantable neuro stimulator of the failure and/or takes appropriate corrective measures.

Claims

1. An implantable medical device having capacitive element failure detection capability comprising in combination:

(a) at least one regulator module capable of providing stimulation energy to at least one electrode;

(b) a capacitive element between the regulator module and the electrode capable of maintaining a charge balance during electrical stimulation; and

(c) a therapy measurement device receiving charge information for the capacitive element and configured to determine whether the capacitive element is malfunctioning based on the charge information.

2. The implantable medical device of claim 1, wherein the therapy measurement device receives charge information selected from the group consisting of voltage drop information across the capacitive element, energy information going in an out of the capacitive element, and current information going in an out of the capacitive element.

3. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that falls outside a predefined range, providing a charge balance pulse in an amount to compensate for the capacitive element being outside the predefined range.

4. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that falls outside a predefined range, removing the capacitive element from service.

5. The implantable medical device of claim 4, wherein the therapy measurement device is further configured to perform the step of:

(ii) if the capacitive element has a charge value that falls outside a predefined range, providing a charge balance pulse in an amount to compensate for the capacitive element being outside the predefined range.

6. The implantable medical device of claim 4, wherein the therapy measurement device is further configured to perform the step of:

(ii) if the capacitive element has a charge value that falls outside a predefined range, providing another capacitive element to maintain a charge balance during electrical stimulation.

7. The implantable medical device of claim 5, wherein the therapy measurement device is configured to perform the step of:

(iii) notifying the implantable medical device of use of the another capacitive element.

8. The implantable medical device of claim 5, wherein the therapy measurement device is configured to perform the step of:

(iii) notifying a physician programmer via telemetry of use of the another capacitive element.

9. The implantable medical device of claim 5, wherein the therapy measurement device is further configured to perform the step of:

(iii) repeating steps (i)-(ii) for each capacitive element.

10. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that is below a predefined value indicative of a possible malfunctioning capacitor, removing the capacitive element from service.

11. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that is above a predefined value indicative of a possible malfunctioning capacitor, removing the capacitive element from service.

12. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that falls outside a predefined range, removing a regulator module corresponding to the capacitive element from service.

13. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that falls outside a predefined range, notifying the implantable medical device of capacitive element malfunction.

14. The implantable medical device of claim 1, wherein the therapy measurement device is configured to perform the step of:

(i) if the capacitive element has a charge value that falls outside a predefined range, notifying a physician programmer via telemetry of capacitive element malfunction.

15. The implantable medical device of claim 1, further comprising:

(d) a waveform generator capable of forming stimulation waveforms; and

(e) a waveform controller coupled to the waveform generator capable of configuring the controller to deliver the stimulation waveforms to the electrode.

16. A method for detecting possible failure of a capacitive element in an implantable medical device comprising the steps of:

(a) providing stimulation energy to at least one electrode;

(b) maintaining a charge balance during electrical stimulation using a capacitive element;

(c) sensing a charge value for the capacitive element; and

(d) determining whether the capacitive element is malfunctioning based on the sensed charge value.

17. The method for detecting possible failure of a capacitive element of claim 16, wherein the step of sensing includes the step of sensing a charge value selected from the group consisting of a voltage drop across the capacitive element, an energy differential between energies going in an out of the capacitive element, and a current differential between currents going in an out of the capacitive element.

18. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that falls outside a predefined range, providing a charge balance pulse in an amount to compensate for the capacitive element being outside the predefined range.

19. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that falls outside a predefined range, removing the capacitive element from service.

20. The method for detecting possible failure of a capacitive element of claim 19, further comprising the step of:

(f) if the capacitive element has a charge value that falls outside a predefined range, providing another capacitive element to maintain a charge balance during electrical stimulation.

21. The method for detecting possible failure of a capacitive element of claim 20, further comprising the step of:

(g) repeating steps (c)-(f) for each capacitive element.

22. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that falls outside a predefined range, removing a controller corresponding to the capacitive element from service.

23. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that falls outside a predefined range, notifying the implantable medical device of capacitive element failure.

24. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that falls outside a predefined range, shutting down the implantable medical device.

25. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that falls outside a predefined range, notifying a physician programmer via telemetry of capacitive element failure.

26. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that is below a predefined value indicative of a possible malfunctioning capacitor, removing the capacitive element from service

27. The method for detecting possible failure of a capacitive element of claim 16, further comprising the step of:

(e) if the capacitive element has a charge value that is above a predefined value indicative of a possible malfunctioning capacitor, removing the capacitive element from service

28. An implantable medical device having capacitive element failure detection capability comprising in combination:

(a) at least one regulator module capable of providing stimulation energy to at least one electrode;

(b) a capacitive element between the regulator module and the electrode capable of maintaining a charge balance during electrical stimulation;

(c) a therapy measurement device receiving as voltage drop information across the capacitive element and configured to perform the following steps if the capacitive element has a voltage drop that falls outside a predefined range;

i) removing the capacitive element from service;

ii) providing another capacitive element to maintain a charge balance during electrical stimulation; and

iii) notifying the implantable medical device of capacitive element failure;

(d) a waveform generator capable of forming stimulation waveforms; and

(e) a waveform controller coupled to the waveform generator capable of configuring the controller to deliver the stimulation waveforms to the electrode.

29. An implantable medical device having capacitive element failure detection capability comprising in combination:

(a) a battery for use with the the implantable medical device;

(b) a holding capacitor for measuring charge information for various components of the implantable medical device, the holding capacitor capable of being coupled to the battery; and

(c) a therapy measurement device coupled to the holding capacitor and configured to receive voltage information for the battery and to determine whether the holding capacitor is malfunctioning based on the voltage information.

30. The implantable medical device of claim 29, wherein the therapy measurement device is configured to performs the steps of:

(i) receiving voltage information for the battery for a first time period;

(ii) receiving voltage information for the battery for a second time period; and

(iii) determining whether the holding capacitor is malfunctioning based on the voltage information for the first and second periods.

31. The implantable medical device of claim 30, wherein the therapy measurement device is configured to performs the additional step of:

(iv) if battery voltage is below a predetermined base level, determining that the holding capacitor is malfunctioning.

32. An implantable medical device having capacitive element failure detection capability comprising in combination:

(a) a battery for use with the the implantable medical device;

(b) a first holding capacitor for measuring charge information for various components of the implantable medical device, the first holding capacitor capable of being coupled to the battery;

(c) a second holding capacitor for measuring charge information for various components of the implantable medical device, the second holding capacitor capable of being coupled to the battery; and

(d) a therapy measurement device coupled to the first and second holding capacitors and configured to receive voltage information for the battery and to determine whether the first or second holding capacitor is malfunctioning based on the voltage information.

33. The implantable medical device of claim 32, wherein the therapy measurement device is configured to performs the steps of:

(i) receiving a first voltage information for the battery via the holding capacitor;

(ii) receiving a second voltage information for the battery via the second holding capacitor; and

(iii) determining whether the holding capacitor or the second holding capacitor is malfunctioning based on the first and second voltage information.

34. The implantable medical device of claim 32, wherein the therapy measurement device is configured to performs the steps of:

(i) receiving a first voltage information for the battery via the holding capacitor; and

(ii) determining whether the holding capacitor is malfunctioning if the first voltage information is outside a predefined range of possible battery voltages.