MONITORING MULTI-CELL POWER SOURCE OF AN IMPLANTABLE MEDICAL DEVICE

• US 20160067510A1
• Filed: 04/24/2015
• Published: 03/10/2016
• Est. Priority Date: 09/08/2014
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Norton, John D., Schmidt, Craig L.
• Granted Patent: US 9,861,828 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3975 Power supply A61N1/378 takes precedence

Abstract

An implantable medical device includes a low-power circuit and a multi-cell power source. The cells of the power source are coupled in a parallel configuration. The implantable medical device includes both a low power circuit and a high power circuit that are coupled between the first and second cells. An isolation circuit is coupled to the first cell and the second cell in a safe parallel orientation and the first and second cells are configured in a first configuration to deliver energy to the low power circuit segment and in a second configuration that is different from the first configuration to deliver energy to the high power circuit segment. A monitoring circuit is coupled to the power source and operable to evaluate the first cell and the second cell to detect a fault condition associated with at least one of the first and second cells.

Claims

1. An implantable medical device, comprising:

operational circuitry having a low power circuit segment and a high power circuit segment;

a power source having at least first and second cells coupled to the operational circuitry;

an isolation circuit connected to the first and second cells and operable to couple the first and second cells in a safe parallel orientation, wherein the first and second cells are configured in a first configuration to deliver energy to the low power circuit segment and in a second configuration that is different from the first configuration to deliver energy to the high power circuit segment; and

a monitoring circuit coupled to the power source and operable to compute a first value corresponding to a parameter of the first cell and a second value corresponding to the parameter of the second cell, wherein the monitoring circuit evaluates the first value and the second value to detect a fault condition associated with at least one of the first and second cells.

2. The implantable medical device of claim 1, wherein the isolation circuit is configured having an impedance that permits the isolation circuit to be bypassed during delivery of energy from the first and second cells to the high power circuit segment.

3. The implantable medical device of claim 1, wherein the monitoring circuit measures a current flowing through each of the first and second cells to compute the first and second values.

4. The implantable medical device of claim 1, wherein the monitoring circuit measures an output voltage of each of the first and second cells to compute the first and second values.

5. The implantable medical device of claim 1, wherein the parameter corresponds to an amount of residual energy within each of the first and second cells.

6. The implantable medical device of claim 1, wherein the parameter comprises at least one of an output voltage, an internal cell impedance, and a current delivered across a load coupled to each of the first and second cells.

7. The implantable medical device of claim 1, wherein the evaluation by the monitoring circuit comprises comparing the first value to the second value to detect the fault condition associated with at least one of the first and second cells.

8. The implantable medical device of claim 1, wherein the fault condition comprises at least one of a high resistance, a loss of capacity, and a high self-discharge.

9. The implantable medical device of claim 1, further comprising a communications module operable to issue an alert based on the detection of the fault condition associated with at least one of the first and second cells.

10. The implantable medical device of claim 1, wherein the first value and the second value are converted into an estimate of remaining longevity of the power source based on a comparison of the first and second values to a predetermined value.

11. The implantable medical device of claim 10, wherein the predetermined value is stored in a look-up table.

12. The implantable medical device of claim 1, further comprising a control circuit operable to selectively configure the first and second cells in the first and second configurations,

wherein only one of the first cell or second cell delivers energy to the low power circuit segment in the first configuration, and

wherein the first cell and second cell synchronously deliver energy to the high power circuit segment in the second configuration.

13. The implantable medical device of claim 1, further comprising a memory having a look-up table including at least one predetermined value, wherein the evaluation by the monitoring circuit comprises comparing each of the first and second values to the predetermined value to detect the fault condition associated with at least one of the first and second cells.

14. The implantable medical device of claim 1, further comprising a voltage converter for converting the first value and the second value into an estimate of remaining longevity of the power source.

15. The implantable medical device of claim 1, wherein the monitoring circuit further compares the first value to the second value to estimate a remaining longevity of the power source.

16. An implantable medical device, comprising:

operational circuitry having a low power circuit segment and a high power circuit segment;

a power source having at least first and second cells coupled to the operational circuitry;

means for isolating the first cell from the second cell to configure the first and second cells in a safe parallel orientation, wherein the first and second cells are arranged in a first configuration to deliver energy to the low power circuit segment and a second configuration that is different from the first configuration to deliver energy to the high power circuit segment; and

means for monitoring the power source to compute a first value corresponding to a parameter of the first cell and a second value corresponding to the parameter of the second cell, wherein the monitoring circuit evaluates the first value and the second value to detect a fault condition associated with at least one of the first and second cells.

17. The implantable medical device of claim 16, further comprising means for selectively configuring the first and second cells in one of the first and second configurations, wherein in the first configuration, only one of the first cell or second cell delivers energy to the low power circuit segment, and

wherein in the second configuration, the first cell and second cell simultaneously deliver energy to the high power circuit segment.

18. The implantable medical device of claim 16, wherein the means for isolation is configured having an impedance that permits the first cell to be isolated from the second cell during delivery of energy to the low power circuit segment in the first configuration, and

wherein the impedance permits the means for isolation to be bypassed during delivery of energy from the power source to the high power circuit segment in the second configuration.

19. The implantable medical device of claim 16, wherein the evaluation by the means for monitoring comprises comparing the first value to the second value to detect the fault condition.

20. The implantable medical device of claim 16, further comprising storage means including at least one predetermined value, wherein the means for monitoring compares the at least one predetermined value to the first and second values to detect the fault condition.

21. The implantable medical device of claim 16, wherein monitoring means further compares the first value to the second value to estimate a remaining longevity of the power source.

22. The implantable medical device of claim 16, wherein the monitoring means measures a current flowing through from each of the first and second cells to compute the first and second values.