Variable recharge determination for an implantable medical device and method therefore

• US 20070255354A1
• Filed: 04/28/2006
• Published: 11/01/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Wahlstrand, Carl, Schmidt, Craig, Scott, Erik, Skime, Robert
• Granted Patent: US 7,616,995 B2
• Time in Patent Office: Days
• US Class Current: 607/63
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

Implantable medical device adapted to provide a therapeutic output to a patient. A therapy module, operatively coupled to a battery, is adapted to provide the therapeutic output. A control circuit provides an action indicative of recharging the battery when the voltage of the battery reaches a recharge voltage wherein the recharge voltage is varied as the battery ages. Also a method of providing a therapeutic output to a patient using an implantable medical device having a battery having a voltage. An action indicative of recharging the battery is provided when the voltage of the battery reaches a recharge voltage. The recharge voltage is varied as the battery ages.

Claims

1. An implantable medical device adapted to provide a therapeutic output to a patient, comprising:

a battery having a voltage;

a therapy module, operatively coupled to said battery, adapted to provide said therapeutic output;

a control circuit, operatively coupled to said battery, providing an action indicative of recharging said battery when said voltage of said battery reaches a recharge voltage;

wherein said recharge voltage is varied as said battery ages.

2. An implantable medical device as in claim 1 wherein said recharge voltage is decreased in value as said battery ages.

3. An implantable medical device as in claim 1 wherein said battery has a fully charged capacity that declines as said battery ages and wherein said recharge voltage is varied in order to tend to equalize a value of a difference in voltage between a fully charged voltage and said recharge voltage as said battery ages.

4. An implantable medical device as in claim 3 wherein said difference is maintained to be approximately equal.

5. An implantable medical device as in claim 1 wherein said battery has a fully charged capacity that declines as said battery ages and wherein said recharge voltage is varied in order to tend to equalize an amount of charge imparted to said battery during recharge between a fully charged voltage and said recharge voltage.

6. An implantable medical device as in claim 5 wherein said charge is maintained as approximately equal as said battery ages.

7. An implantable medical device as in claim 1 wherein said action comprises indicating that said battery should be recharged.

8. An implantable medical device as in claim 1 wherein said voltage is varied such that a time between a first recharge of said battery and a second recharge of said battery is made more uniform as said battery ages.

9. An implantable medical device as in claim 8 wherein said time is approximately equal.

10. An implantable medical device as in claim 1 wherein said recharge voltage is increased in value as said battery ages.

11. An implantable medical device as in claim 10 wherein said battery has an off voltage below which said therapy module of said implantable medical device may cease to operate properly, wherein said implantable medical device has a patient recharge compliance period commencing upon said action and ending when said voltage of said battery reaches said off voltage and wherein said recharge voltage is varied such that said patient recharge compliance period is maintained to be more uniform as said battery ages.

12. An implantable medical device as in claim 10 wherein said battery has an off voltage below which said therapy module of said implantable medical device may cease to operate properly, wherein said implantable medical device has a patient recharge compliance period commencing upon said action and ending when said voltage of said battery reaches said off voltage and wherein said recharge voltage is varied in order to tend to equalize an amount of charge remaining in said battery during said patient recharge compliance period.

13. An implantable medical device as in claim 12 wherein said charge is maintained as approximately equal as said battery ages.

14. An implantable medical device as in claim 11 wherein said recharge voltage is varied in order that said patient recharge compliance period is maintained to be approximately equal as said battery ages.

15. An implantable medical device as in claim 1 wherein said recharge voltage is decreased in value as said battery ages in an early stage of a life of said battery and wherein said recharge voltage is increased in value as said battery ages in a later stage of said life of said battery.

16. The implantable medical device as in claim 1 wherein said recharge voltage is increased in value as said battery ages in an early stage of a life of said battery and wherein said recharge voltage is decreased in value as said battery ages in a later stage of said life of said battery.

17. A method of providing a therapeutic output to a patient using an implantable medical device having a battery having a voltage, comprising:

providing an action indicative of recharging said battery when said voltage of said battery reaches a recharge voltage; and

varying said recharge voltage as said battery ages.

18. A method as in claim 17 wherein said recharge voltage in said varying step is decreased in value as said battery ages.

19. A method as in claim 17 wherein said battery has a fully charged capacity that declines as said battery ages and wherein said recharge voltage is varied in order to tend to equalize a value of a difference in voltage between a fully charged voltage and said recharge voltage as said battery ages.

20. A method as in claim 19 wherein said difference is maintained to be approximately equal.

21. A method as in claim 17 wherein said battery has a fully charged capacity that declines as said battery ages and wherein said recharge voltage is varied in order to tend to equalize an amount of charge imparted to said battery during recharge between a fully charged voltage and said recharge voltage.

22. A method as in claim 21 wherein said charge is maintained as approximately equal as said battery ages.

23. A method as in claim 24 wherein said action step comprises indicating that said battery should be recharged.

24. A method as in claim 17 wherein said voltage is varied such that a time between a first recharge of said battery and a second recharge of said battery is made more uniform as said battery ages.

25. A method as in claim 24 wherein said time is approximately equal.

26. A method as in claim 17 wherein said recharge voltage is increased in value as said battery ages.

27. A method as in claim 26 wherein said battery has an off voltage below which said therapy module of said implantable medical device may cease to operate properly, wherein said implantable medical device has a patient recharge compliance period commencing upon said action and ending when said voltage of said battery reaches said off voltage and wherein said recharge voltage is varied such that said patient recharge compliance period is maintained to be more uniform as said battery ages.

28. A method as in claim 26 wherein said battery has an off voltage below which said therapy module of said implantable medical device may cease to operate properly, wherein said implantable medical device has a patient recharge compliance period commencing upon said action and ending when said voltage of said battery reaches said off voltage and wherein said recharge voltage is varied in order to tend to equalize an amount of charge remaining in said battery during said patient recharge compliance period.

29. A method as in claim 28 wherein said charge is maintained as approximately equal as said battery ages.

30. A method as in claim 27 wherein said recharge voltage is varied in order that said patient recharge compliance period is maintained to be approximately equal as said battery ages.

31. A method as in claim 17 wherein said recharge voltage is decreased in value as said battery ages in an early stage of a life of said battery and wherein said recharge voltage is increased in value as said battery ages in a later stage of said life of said battery.

32. A method as in claim 17 wherein said recharge voltage is increased in value as said battery ages in an early stage of a life of said battery and wherein said recharge voltage is decreased in value as said battery ages in a later stage of said life of said battery.

33. An implantable medical device adapted to provide a therapeutic output to a patient, comprising:

a battery having a voltage;

a therapy module, operatively coupled to said battery, adapted to provide said therapeutic output;

a control circuit, operatively coupled to said battery, including means for providing an action indicative of recharging said battery when said voltage of said battery reaches a recharge voltage;

wherein said means includes means for varying the recharge voltage as said battery ages.

34. An implantable medical device as in claim 33 wherein said battery has an off voltage below which said therapy module of said implantable medical device may cease to operate properly, wherein said implantable medical device has a patient recharge compliance period commencing upon said action and ending when said voltage of said battery reaches said off voltage and wherein said means for varying the recharge voltage as said battery ages includes means for varying said recharge voltage such that said patient recharge compliance period is maintained to be more uniform as said battery ages.

35. An implantable medical device as in claim 33 wherein said battery has an off voltage below which said therapy module of said implantable medical device may cease to operate properly, wherein said implantable medical device has a patient recharge compliance period commencing upon said action and ending when said voltage of said battery reaches said off voltage and wherein said means for varying the recharge voltage as said battery ages includes means for varying said recharge voltage in order to tend to equalize an amount of charge remaining in said battery during said patient recharge compliance period.

36. An implantable medical device as in claim 33 wherein the means for varying the recharge voltage as said battery ages includes means for decreasing said recharge voltage in value as said battery ages in an early stage of a life of said battery and increasing said recharge voltage in value as said battery ages in a later stage of said life of said battery.