Determining and forecasting end of life for an implantable medical device having a rechargeable battery

• US 9,887,573 B2
• Filed: 09/15/2016
• Issued: 02/06/2018
• Est. Priority Date: 01/16/2014
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Marnfeldt, Goran N., Carbunaru, Rafael, Parramon, Jordi
• Primary Examiner(s): Wieland, Robert N
• Application Number:
  US15/266,669
• Publication Number:
  US 20170005486A1
• Time in Patent Office: 509 Days
• CPC Class Codes: A61N 1/36128 Control systems
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]

Abstract

An algorithm programmed into the control circuitry of a rechargeable-battery Implantable Medical Device (IMD) is disclosed that can quantitatively forecast and determine the timing of an early replacement indicator (tEOLi) and an IMD End of Life (tEOL). These forecasts and determinations of tEOLi and tEOL occur in accordance with one or more parameters having an effect on rechargeable battery capacity, such as number of charging cycles, charging current, discharge depth, load current, and battery calendar age. The algorithm consults such parameters as stored over the history of the operation of the IMD in a parameter log, and in conjunction with a battery capacity database reflective of the effect of these parameters on battery capacity, determines and forecasts tEOLi and tEOL. Such forecasted or determined values may also be used by a shutdown algorithm to suspend therapeutic operation of the IMD.

Claims

1. Circuitry for a medical device, comprising:

a rechargeable battery;

control circuitry configured to forecast an end of life of the medical device using estimates of a capacity of the battery at different points in time during operation of the medical device;

a first register configured to store the forecasted end of life; and

telemetry circuitry configured to telemeter the forecasted end of life from the first register to an external device.

2. The circuitry of claim 1, wherein the control circuitry forecasts the end of life as a time at which the battery is expect to reach a first capacity threshold.

3. The circuitry of claim 1, wherein the control circuitry is further configured to forecast an early replacement indicator preceding the forecasted end of life, and further comprising a second register configured to store the forecasted early replacement indicator, wherein the telemetry circuitry is further configured to telemeter the forecasted early replacement indicator from the second register to the external device.

4. The circuitry of claim 1, wherein the early replacement indicator is forecasted using the forecasted end of life.

5. The circuitry of claim 4, wherein the forecasted early replacement indicator comprises a set time before the forecasted end of life.

6. The circuitry of claim 3, wherein the control circuitry is configured to forecast the early replacement indicator using the estimates of the capacity of the battery at the different points in time during operation of the medical device.

7. The circuitry of claim 6, wherein the control circuitry forecasts the early replacement indicator as a second time at which the battery is expect to reach a second capacity threshold, and wherein the control circuitry forecasts the end of life as a first time later than a second time at which the battery is expect to reach a first capacity threshold lower than the second capacity threshold.

8. The circuitry of claim 1, wherein the control circuitry is further configured to suspend therapeutic operation of the medical device when the forecasted end of life has been reached.

9. The circuitry of claim 1, further comprising a third register configured to store a shutdown time at which therapeutic operation of the medical device is normally suspended.

10. The circuitry of claim 9, wherein if the stored shutdown time has been reached and is earlier than the forecasted end of life, the control circuitry is further configured to extend therapeutic operation of the medical device beyond the shutdown time.

11. The circuitry of claim 9, wherein if the stored forecasted end of life has been reached and is earlier than the shutdown time, the control circuitry is configured to suspend therapeutic operation of the medical device.

12. The circuitry of claim 1, further comprising:

memory configured to store at least one parameter having an effect on the capacity of the rechargeable battery, wherein the at least one parameter comprises one or more of;

at least one first parameter determined during previous charging of the battery, at least one second parameter determined during previous use of the medical device to provide therapy, and an age of the battery,

wherein the control circuitry is configured to estimate the capacity of the battery at the different points in time using the at least one parameter.

13. The circuitry of claim 1, wherein the control circuitry is configured during operation of the medical device to update the forecasted end of life stored in the first register.

14. The circuitry of claim 1, wherein the telemetry circuitry is configured to telemeter the forecasted end of life upon receipt of a command from the external device, or when the external device initiates a communication session with the medical device.

15. Circuitry for a medical device, comprising:

a rechargeable battery;

control circuitry configured to forecast an end of life of the medical device using estimates of a capacity of the battery at different points in time during operation of the medical device, and configured to forecast an early replacement indicator preceding the forecasted end of life;

a first memory configured to store a first indicator that the forecasted end of life has been reached;

a second memory configured to store a second indicator that the forecasted early replacement indicator has been reached; and

telemetry circuitry configured to telemeter the first indicator from the first memory and the second indicator from the second memory to an external device.

16. The circuitry of claim 15, wherein the control circuitry forecasts the end of life as a time at which the battery is expect to reach a first capacity threshold.

17. The circuitry of claim 15, wherein the early replacement indicator is forecasted using the forecasted end of life.

18. The circuitry of claim 17, wherein the forecasted early replacement indicator comprises a set time before the forecasted end of life.

19. The circuitry of claim 15, wherein the control circuitry is configured to forecast the early replacement indicator using the estimates of the capacity of the battery at the different points in time during operation of the medical device.

20. The circuitry of claim 19, wherein the control circuitry forecasts the early replacement indicator as a second time at which the battery is expect to reach a second capacity threshold, and wherein the control circuitry forecasts the end of life as a first time later than a second time at which the battery is expect to reach a first capacity threshold lower than the second capacity threshold.

21. The circuitry of claim 15, wherein the control circuitry is further configured to suspend therapeutic operation of the medical device when the forecasted end of life has been reached.

22. The circuitry of claim 15, further comprising a register comprising a shutdown time at which therapeutic operation of the medical device is normally suspended.

23. The circuitry of claim 22, wherein if the shutdown time has been reached and is earlier than the forecasted end of life, the control circuitry is further configured to extend therapeutic operation of the medical device beyond the shutdown time.

24. The circuitry of claim 22, if the forecasted end of life has been reached and is earlier than the shutdown time, the control circuitry is configured to suspend therapeutic operation of the medical device.

25. The circuitry of claim 15, further comprising:

a third memory configured to store at least one parameter having an effect on the capacity of the rechargeable battery, wherein the at least one parameter comprises one or more of;

at least one first parameter determined during previous charging of the battery, at least one second parameter determined during previous use of the medical device to provide therapy, and an age of the battery,

wherein the control circuitry is configured to estimate the capacity of the battery at the different points in time using the at least one parameter.

26. The circuitry of claim 15, wherein the control circuitry is configured during operation of the medical device to update the forecasted end of life and the forecasted early replacement indicator.

27. The circuitry of claim 15, wherein the telemetry circuitry is configured to telemeter the first indicator and the second indicator upon receipt of a command from the external device, or when the external device initiates a communication session with the medical device.