CHARGE LEVEL MEASUREMENT

• US 20110307033A1
• Filed: 06/14/2010
• Published: 12/15/2011
• Est. Priority Date: 06/14/2010
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Michaels, Matthew J., Anderson, Joel A., Cerny, Douglas S.
• Granted Patent: US 8,942,935 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC

Abstract

This disclosure describes techniques for estimating an amount of charge on a power source. A processor may determine an uncertainty value associated with a first charge level of a power source and an uncertainty value associated with a second charge level of the power source. Based on the uncertainties, the processor may adjust the first charge level to generate an adjusted charge level. The processor may further adjust the adjusted charge level based on the behavior of the power source.

Claims

1. A method comprising:

determining, with a processor associated with a medical device, a first uncertainty value associated with a first charge level estimate of a power source and a second uncertainty value associated with a second charge level estimate of the power source; and

adjusting, with the processor, the first charge level estimate based on at least the first and second uncertainty values to generate an adjusted charge level estimate.

2. The method of claim 1, wherein the first and second charge level estimates each comprise one of a charge level derived from a measurement by a coulomb counter, and a charge level derived from one of a voltage, pressure, temperature, impedance, or size of the power source.

3. The method of claim 1, further comprising:

determining a third uncertainty value associated with a third charge level estimate of the power source,

wherein adjusting the first charge level estimate comprises adjusting the first charge level estimate based on at least the first, second, and third uncertainty values to generate the adjusted charge level estimate.

4. The method of claim 1, wherein each of the first and second charge level estimates and the adjusted charge level estimate indicate an amount of charge remaining on the power source.

5. The method of claim 1, wherein each of the first and second charge level estimates and the adjusted charge level estimate indicate a percentage of charge remaining on the power source.

6. The method of claim 1, wherein each of the first and second charge level estimates and the adjusted charge level estimate indicate a remaining amount of operation time of the power source.

7. The method of claim 1, wherein the medical device comprises an implantable medical device (IMD), and wherein the IMD includes the processor.

8. The method of claim 1, wherein the medical device comprises a programmer, and wherein the programmer includes the processor.

9. The method of claim 1, wherein determining the first uncertainty value comprises determining the first uncertainty value based on a stored indication of the first uncertainty value, and wherein determining the second uncertainty value comprises determining the second uncertainty value based on a stored indication of the second uncertainty value.

10. The method of claim 1, further comprising:

comparing the first and second uncertainty values to determine whether the first uncertainty value is greater than the second uncertainty value,

wherein adjusting the first charge level estimate comprises setting the first charge level estimate to a substantially similar level as the second charge level estimate when the first uncertainty value is greater than the second uncertainty value.

11. The method of claim 1, wherein adjusting the first charge level estimate comprises:

determining a first maximum charge level estimate based on the first charge level estimate and the first uncertainty value;

determining a second maximum charge level estimate based on the second charge level estimate and the second uncertainty value;

comparing the first and second maximum charge level estimates; and

adjusting the first charge level estimate based on the comparison.

12. The method of claim 11, further comprising:

determining whether the first maximum charge level estimate is greater than the second maximum charge level estimate;

determining a first minimum charge level estimate based on the first charge level estimate and the first uncertainty value when the first maximum charge level estimate is greater than the second maximum charge level estimate;

comparing the first minimum charge level estimate with the second maximum charge level estimate when the first charge level estimate is greater than the second charge level estimate; and

further adjusting the adjusted charge level estimate based on the comparison.

13. The method of claim 1, wherein adjusting the first charge level estimate comprises:

determining a first minimum charge level estimate based on the first charge level estimate and the first uncertainty value;

determining a second minimum charge level estimate based on the second charge level estimate and the second uncertainty value;

comparing the first and second minimum charge level estimates; and

adjusting the first charge level estimate based on the comparison.

14. The method of claim 13, further comprising:

determining whether the first minimum charge level estimate is less than the second minimum charge level estimate;

determining a first maximum charge level estimate based on the first charge level estimate and the first uncertainty value when the first minimum charge level estimate is less than the second minimum charge level estimate;

comparing the first maximum charge level estimate with the second minimum charge level estimate when the first minimum charge level estimate is less than the second minimum charge level estimate; and

further adjusting the adjusted charge level estimate based on the comparison.

15. The method of claim 1, further comprising:

transmitting the adjusted charge level estimate for presentation.

16. The method of claim 1, further comprising:

subtracting an uncertainty value associated with the adjusted charge level estimate to generate a minimum adjusted charge level estimate; and

transmitting the minimum adjusted charge level estimate for presentation.

17. A medical device system comprising:

a power source; and

a processor configured to;

determine a first uncertainty value associated with a first charge level estimate of the power source and a second uncertainty value associated with a second charge level estimate of the power source; and

adjust the first charge level estimate based on at least the first and second uncertainty values to generate an adjusted charge level estimate.

18. The system of claim 17, wherein the first and second charge level estimates each comprise one of a charge level derived from a measurement by a coulomb counter, and a charge level derived from one of a voltage, pressure, temperature, impedance, or size of the power source.

19. The system of claim 17, wherein the processor is further configured to:

determine a third uncertainty value associated with a third charge level estimate of the power source,

wherein the processor is configured to adjust the first charge level estimate based on at least the first, second, and third uncertainty values to generate the adjusted charge level estimate.

20. The system of claim 17, wherein each of the first and second charge level estimates and the adjusted charge level estimate indicate an amount of charge remaining on the power source.

21. The system of claim 17, wherein each of the first and second charge level estimates and the adjusted charge level estimate indicate a percentage of charge remaining on the power source.

22. The system of claim 17, wherein each of the first and second charge level estimates and the adjusted charge level estimate indicate a remaining amount of operation time of the power source.

23. The system of claim 17, further comprising an IMD, wherein the IMD includes the power source and the processor.

24. The system of claim 17, further comprising a programmer, wherein the programmer includes the processor.

25. The system of claim 17, wherein the processor is configured to determine the first uncertainty value based on a stored indication of the first uncertainty value, and wherein the processor is configured to determine the second uncertainty value based on a stored indication of the second uncertainty value.

26. The system of claim 17, wherein the processor is further configured to:

compare the first and second uncertainty values to determine whether the first uncertainty value is greater than the second uncertainty value,

wherein the processor sets the first charge level estimate to a substantially similar level as the second charge level estimate when the first uncertainty value is greater than the second uncertainty value to adjust the first charge level estimate.

27. The system of claim 17, wherein the processor is further configured to:

determine a first maximum charge level estimate based on the first charge level estimate and the first uncertainty value;

calculate a second maximum charge level estimate based on the second charge level estimate and the second uncertainty value; and

compare the first and second maximum charge level estimates,

wherein the processor adjusts the first charge level estimate based on the comparison.

28. The system of claim 27, wherein the processor is further configured to:

determine whether the first maximum charge level estimate is greater than the second maximum charge level estimate;

determine a first minimum charge level estimate based on the first charge level estimate and the first uncertainty value when the first maximum charge level estimate is greater than the second maximum charge level estimate;

compare the first minimum charge level estimate with the second maximum charge level estimate when the first maximum charge level estimate is greater than the second maximum charge level estimate; and

further adjust the adjusted charge level estimate based on the comparison.

29. The system of claim 17, wherein the processor is further configured to:

determine a first minimum charge level estimate based on the first charge level estimate and the first uncertainty value;

determine a second minimum charge level estimate based on the second charge level estimate and the second uncertainty value; and

compare the first and second minimum charge level estimates,

wherein the processor adjusts the first charge level estimate based on the comparison.

30. The system of claim 29, wherein the processor is further configured to:

determine whether the first minimum charge level estimate is less than the second minimum charge level estimate;

determine a first maximum charge level estimate based on the first charge level estimate and the first uncertainty value when the first minimum charge level estimate is less than the second minimum charge level estimate;

compare the first maximum charge level estimate with the second minimum charge level estimate when the first minimum charge level estimate is less than the second minimum charge level estimate; and

further adjust the adjusted charge level estimate based on the comparison.

31. The system of claim 17, further comprising:

a telemetry module configured to transmit the adjusted charge level estimate for presentation.

32. The system of claim 17, further comprising:

a telemetry module,

wherein the processor is further configured to subtract an uncertainty value associated with the adjusted charge level estimate to generate a minimum adjusted charge level estimate, and

wherein the telemetry module is configured to transmit the minimum adjusted charge level estimate for presentation.

33. A non-transitory computer-readable storage medium comprising instructions that cause one or more processors in a medical device to:

determine a first uncertainty value associated with a first charge level estimate of a power source and a second uncertainty value associated with a second charge level estimate of the power source; and

adjust the first charge level estimate based on at least the first and second uncertainty values to generate an adjusted charge level estimate.

34. A medical device system comprising:

means for determining a first uncertainty value associated with a first charge level estimate of a power source and a second uncertainty value associated with a second charge level estimate of the power source; and

means for adjusting the first charge level estimate based on at least the first and second uncertainty values to generate an adjusted charge level estimate,

wherein at least one of the means for determining and the means for adjusting is implemented at least partially as hardware.