Charge level measurement

• US 8,942,935 B2
• Filed: 06/14/2010
• Issued: 01/27/2015
• 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.
• Primary Examiner(s): Moffat, Jonathan C Teixeira
• Assistant Examiner(s): BETSCH, REGIS J
• Application Number:
  US12/815,095
• Publication Number:
  US 20110307033A1
• Time in Patent Office: 1,688 Days
• Field of Search: 702/63
• US Class Current: 702/63
• 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:

measuring a first estimated value of a charge level of a power source associated with a medical device using a first unit;

measuring a second estimated value of the charge level of the power source using a second unit;

determining, with a processor, a first margin of uncertainty associated with the first estimated value of the charge level of the power source and a second margin of uncertainty associated with the second estimated value of the charge level of the power source;

at least one of;

determining a first value based on an addition of the first margin of uncertainty to the first estimated value of the charge level, and a second value based on an addition of the second margin of uncertainty to the second estimated value of the charge level;

or

determining a third value based on a subtraction of the first margin of uncertainty from the first estimated value of the charge level, and a fourth value based on a subtraction of the second margin of uncertainty from the second estimated value of the charge level;

at least one of comparing the first value and the second value or comparing the third value and the fourth value; and

adjusting, with the processor, the first estimated value of the charge level based on at least the comparison to generate an adjusted estimated value of the charge level.

2. The method of claim 1, wherein the first unit and the second unit are different, and wherein the first estimated value of the charge level comprises one of a charge level value derived from a measurement by a coulomb counter, or a charge level value derived from one of a voltage, pressure, temperature, impedance, or size of the power source, and wherein the second estimated value of the charge level comprises one of a charge level value derived from the measurement by the coulomb counter, or the charge level value derived from one of the voltage, pressure, temperature, impedance, or size of the power source, and that is different from the first estimated value of the charge level.

3. The method of claim 1, further comprising:

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

wherein adjusting the first estimated value of the charge level comprises adjusting the first estimated value of the charge level based on at least the comparison and the third margin of uncertainty to generate the adjusted estimated value of the charge level.

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

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

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

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

8. The method of claim 1, further comprising:

determining whether the first value is greater than the second value based on the comparison;

determining a first minimum value based on the first estimated value of the charge level and the first margin of uncertainty when the first value is greater than the second value;

comparing the first minimum value with the second value when the first value is greater than the second value; and

further adjusting the adjusted estimated value of the charge level based on the comparison of the first minimum value with the second value.

9. The method of claim 1, further comprising:

determining whether the third value is less than the fourth value;

determining a first maximum value based on the first estimated value and the first margin of uncertainty when the third value is less than the fourth value;

comparing the first maximum value with the fourth value when the third value is less than the fourth value; and

further adjusting the adjusted estimated value of the charge level based on the comparison of the first maximum value with the fourth value.

10. The method of claim 1, further comprising:

transmitting the adjusted estimated value of the charge level for presentation.

11. The method of claim 1, further comprising:

subtracting a margin of uncertainty associated with the adjusted estimated value of the charge level from the adjusted estimated value of the charge level to generate a minimum value of the adjusted estimated value of the charge level; and

transmitting the minimum value of the adjusted estimated value of the charge level for presentation.

12. The method of claim 1, wherein determining the third value and the fourth value comprises determining the third value and the fourth value if the first value is less than the second value, and wherein comparing the third value and the fourth value comprises comparing the third value and the fourth value if the first value is less than the second value.

13. A medical device system comprising:

a power source;

a measurement unit configured to measure a first estimated value of a charge level of the power source and a second estimated value of the charge level of the power source; and

a processor configured to;

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

at least one of;

determine a first value based on an addition of the first margin of uncertainty to the first estimated value of the charge level, and a second value based on an addition of the second margin of uncertainty to the second estimated value of the charge level;

or

determine a third value based on a subtraction of the first margin of uncertainty from the first estimated value of the charge level, and a fourth value based on a subtraction of the second margin of uncertainty from the second estimated value of the charge level;

at least one of compare the first value and the second value or compare the third value and the fourth value; and

adjust the first estimated value of the charge level based on at least the comparison to generate an adjusted estimated value of the charge level.

14. The system of claim 13, wherein the measurement unit comprises a first unit and a second, different unit, wherein the first estimated value of the charge level is measured by the first unit and comprises one of a charge level derived from a measurement by a coulomb counter, or a charge level derived from one of a voltage, pressure, temperature, impedance, or size of the power source, and wherein the second estimated value of the charge level is measured by the second unit and comprises one of a charge level value derived from the measurement by the coulomb counter, or the charge level value derived from one of the voltage, pressure, temperature, impedance, or size of the power source, and that is different from the first estimated value of the charge level.

15. The system of claim 13, wherein the processor is further configured to:

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

wherein the processor is configured to adjust the first estimated value of the charge level based on at least the comparison and the third margin of uncertainty to generate the adjusted estimated value of the charge level.

16. The system of claim 13, wherein each of the first and second estimated values of the charge level and the adjusted estimated value of the charge level indicate an amount of charge remaining on the power source.

17. The system of claim 13, wherein each of the first and second estimated values of the charge level and the adjusted estimated value of the charge level indicate a percentage of charge remaining on the power source.

18. The system of claim 13, wherein each of the first and second estimated values of the charge level and the adjusted estimated value of the charge level indicate a remaining amount of operation time of the power source.

19. The system of claim 13, further comprising an implantable medical device (IMD), wherein the IMD includes the power source, the measurement unit, and the processor.

20. The system of claim 13, further comprising an implantable medical device (IMD), and a programmer, wherein the programmer includes the processor, and wherein the IMD includes the power source, and the measurement unit.

21. The system of claim 13, wherein the processor is configured to determine the first margin of uncertainty based on a stored indication of the first margin of uncertainty, and wherein the processor is configured to determine the second margin of uncertainty based on a stored indication of the second margin of uncertainty.

22. The system of claim 13, wherein the processor is further configured to:

determine whether the first value is greater than the second value;

determine a first minimum value based on the first estimated value of the charge level and the first margin of uncertainty when the first value is greater than the second value;

compare the first minimum value with the second value when the first value is greater than the second value; and

further adjust the adjusted estimated value of the charge level based on the comparison of the first minimum value with the second value.

23. The system of claim 13, wherein the processor is further configured to:

determine whether the third value is less than the fourth value;

determine a first maximum value based on the first estimated value and the first margin of uncertainty when the third value is less than the fourth value;

compare the first maximum value with the fourth value when the third value is less than the fourth value; and

further adjust the adjusted estimated value of the charge level based on the comparison of the first maximum value with the fourth value.

24. The system of claim 13, further comprising:

a telemetry module configured to transmit the adjusted estimated value of the charge level for presentation.

25. The system of claim 13, further comprising:

a telemetry module,

wherein the processor is further configured to subtract a margin of uncertainty associated with the adjusted estimated value of the charge level from the adjusted estimated value of the charge level to generate a minimum value of the adjusted estimated value of the charge level, and

wherein the telemetry module is configured to transmit the minimum value of the adjusted estimated value of the charge level for presentation.

26. The system of claim 13, wherein the processor is configured to determine the third value and the fourth value if the first value is less than the second value, and wherein the processor is configured to compare the third value and the fourth value if the first value is less than the second value.

27. The system of claim 13, further comprising a programmer, wherein the programmer includes the power source, the first unit, the second unit, and the processor.

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

receive a first estimated value of a charge level of a power source associated with the medical device from a first unit;

receive a second estimated value of the charge level of the power source associated with the medical device from a second unit;

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

at least one of;

determine a first value based on an addition of the first margin of uncertainty to the first estimated value of the charge level, and a second value based on an addition of the second margin of uncertainty to the second estimated value of the charge level;

or

determine a third value based on a subtraction of the first margin of uncertainty from the first estimated value of the charge level, and a fourth value based on a subtraction of the second margin of uncertainty from the second estimated value of the charge level;

at least one of compare the first value and the second value or compare the third value and the fourth value; and

adjust the first estimated value of the charge level based on at least the comparison to generate an adjusted estimated value of the charge level.