Alignment indication for transcutaneous energy transfer

• US 20060247737A1
• Filed: 04/29/2005
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Olson, David P., Schmeling, Andrew L., Nelson, Steve J.
• Granted Patent: US 7,774,069 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2205/8237 Charging means
• CPC Class Codes: A61M 2205/8287 operated by an external magnetic or electromagnetic field
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

System for transcutaneous energy transfer. An implantable medical device, adapted to be implanted in a patient, has componentry for providing a therapeutic output. The implantable medical device has an internal power source and a secondary coil operatively coupled to the internal power source. An external power source, having a primary coil, provides energy to the implantable medical device when the primary coil of the external power source is placed in proximity of the secondary coil of the implantable medical device and thereby generates a current in the internal power source. An alignment indicator reports the alignment as a function of the current generated in the internal power source with a predetermined value associated with an expected alignment between the primary coil and secondary coil.

Claims

1. A system for transcutaneous energy transfer, comprising:

an implantable medical device having componentry for providing a therapeutic output, said implantable medical device having an internal power source and a secondary coil operatively coupled to said internal power source, said implantable medical device adapted to be implanted in a patient;

an external power source having a primary coil, said external power source providing energy to said implantable medical device when said primary coil of said external power source is placed in proximity of said secondary coil of said implantable medical device and thereby generating a current associated with said internal power source; and

an alignment indicator, operatively coupled to said internal power source, reporting said alignment as a function of said current.

2. The system as in claim 1 wherein said current is compared with a predetermined value associated with an expected alignment between said primary coil and said secondary coil.

3. The system as in claim 2 wherein said internal power source has an internal impedance and wherein said predetermined value is adjusted as a function of said internal impedance of said internal power source.

4. The system as in claim 3 wherein said internal impedance of said power source increases over time.

5. The system as in claim 4 wherein said predetermined value decreases as said internal impedance increases.

6. The system as in claim 2 wherein said internal power source has a voltage and wherein said predetermined value is adjusted as a function of said voltage of said internal power source.

7. The system as in claim 3 wherein said predetermined value decreases as said voltage of said power source decreases.

8. The system as in claim 7 wherein said power source is a battery.

9. The system as in claim 1 wherein said alignment indicator comprises a display.

10. The system as in claim 9 wherein said display comprises a percentage of said current generated in said secondary coil to said predetermined value.

11. The system as in claim 10 wherein said display comprises a bar graph.

12. The system as in claim 1 wherein said expected alignment comprises perfect alignment.

13. The system as in claim 1 wherein said alignment indicator ceases reporting of said alignment following reaching a predetermined point of a charging cycle.

14. The system as in claim 13 wherein said predetermined point of a charging cycle comprises following said internal power source reaching a predetermined voltage.

15. The system as in claim 14 wherein said predetermined voltage is at least ninety percent of a voltage representing an expected full charge of said internal power source.

16. The system as in claim 1 wherein said external power source varies its power output in order to generate a predetermined current in said internal power source.

17. The system as in claim 16 wherein said predetermined current in said internal power source varies as a function of said voltage of said internal power source.

18. The system as in claim 17 wherein said predetermined current in said internal power source declines as said voltage of said internal power source increases during a charging cycle.

19. The system as in claim 16 wherein said predetermined current in said internal power source comprises a maximum amount current for charging said internal power source.

20. The system as in claim 19 wherein said predetermined current in said internal power source declines over time as said internal impedance of the said internal power source increases.

21. An external power system for transcutaneous energy transfer to an implantable medical device having componentry for providing a therapeutic output and a secondary coil operatively coupled to said componentry, said implantable medical device adapted to be implanted in a patient, comprising:

a primary coil providing energy to said implantable medical device when said primary coil is placed in proximity of said secondary coil of said implantable medical device and thereby generating a current in said internal power source; and

an alignment indicator, operatively coupled to said internal power source, reporting said alignment as a function of said current generated in said internal power source with a predetermined value associated with an expected alignment between said primary coil and secondary coil.

22. The external power system as in claim 21 wherein said internal power source has an internal impedance and wherein said predetermined value is adjusted as a function of said internal impedance of said internal power source.

23. The external power system as in claim 22 wherein said internal impedance of said power source increases over time.

24. The external power system as in claim 23 wherein said predetermined value decreases as said internal impedance increases.

25. The external power system as in claim 21 wherein said internal power has a voltage and wherein said predetermined value is adjusted as a function of said voltage of said internal power source.

26. The external power system as in claim 22 wherein said predetermined value decreases as said voltage of said power source decreases.

27. The external power system as in claim 26 wherein said power source is a battery.

28. The external power system as in claim 21 wherein said alignment indicator comprises a display.

29. The external power system as in claim 28 wherein said display comprises a percentage of said current generated in said secondary coil to said predetermined value.

30. The external power system as in claim 28 wherein said display comprises a bar graph.

31. The external power system as in claim 21 wherein said expected alignment comprises perfect alignment.

32. A system for transcutaneous energy transfer, comprising:

an implantable medical device having componentry for providing a therapeutic output, said implantable medical device having an internal power source and a secondary coil operatively coupled to said internal power source, said implantable medical device adapted to be implanted in a patient; and

an external power source having a primary coil, said external power source providing energy to said implantable medical device when said primary coil of said external power source is placed in proximity of said secondary coil of said implantable medical device and thereby generating a current in said internal power source;

said external power source varies its power output in order to generate a predetermined current in said internal power source.

33. The system as in claim 32 wherein said predetermined current in said internal power source varies as a function of said voltage of said internal power source.

34. The system as in claim 33 wherein said predetermined current in said internal power source declines as said voltage of said internal power source increases during a charging cycle.

35. The system as in claim 32 wherein said predetermined current in said internal power source comprises a maximum amount current for charging said internal power source.

36. The system as in claim 35 wherein said predetermined current in said internal power source declines over time as said internal impedance of the said internal power source increases.

37. A method of indicating an alignment between an external primary coil and an inductively coupled secondary coil of an implanted medical device, said secondary coil supplying power to a power source having an internal impedance, comprising the steps of:

driving said external primary coil with a charging signal;

measuring a current generated in said power source by said charging signal;

comparing an amount of said current generated in said power source with a predetermined value associated with an expected alignment between said external primary coil and said secondary coil;

reporting said alignment as a function of said current generated in said secondary coil with said predetermined value from said comparison step; and

adjusting said predetermined value as a function of said internal impedance of said power source.

38. The method as in claim 37 wherein the steps are repeated as said voltage of said power source declines.

39. The method as in claim 38 wherein said power source is a battery.

40. The method as in claim 38 wherein said comparing step determines a percentage of said current generated in said secondary coil to said predetermined value.

41. The method as in claim 40 wherein said reporting step comprises displaying said percentage.

42. The method as in claim 41 wherein said displaying step comprises displaying some of a plurality of steps in a bar graph.

43. The method as in claim 41 wherein said internal impedance of said power source increases over time.

44. The method as in claim 37 further comprising the step of varying a power output of said external power source in order to generate a predetermined current in said internal power source.

45. The method as in claim 44 wherein said predetermined current in said internal power source varies as a function of said voltage of said internal power source.

46. The method as in claim 45 wherein said predetermined current in said internal power source declines as said voltage of said internal power source increases during a charging cycle.

47. The method as in claim 44 wherein said predetermined current in said internal power source comprises a maximum amount current for charging said internal power source.

48. The method as in claim 47 wherein said predetermined current in said internal power source declines over time as said internal impedance of the said internal power source increases.

49. The method of transcutaneous energy transfer between an external primary coil and an inductively coupled secondary coil of an implanted medical device, said secondary coil supplying power to a power source having an internal impedance, comprising the steps of:

driving said external primary coil with a charging signal;

measuring a current generated in said power source by said charging signal; and

varying said charging signal in order to generate a predetermined current in said internal power source.

50. The method as in claim 49 further comprising the step of varying said predetermined current in said internal power source as a function of said voltage of said internal power source.

51. The method as in claim 50 wherein said predetermined current in said internal power source declines as said voltage of said internal power source increases during a charging cycle.

52. The method as in claim 49 wherein said predetermined current in said internal power source comprises a maximum amount current for charging said internal power source.

53. The method as in claim 52 wherein said predetermined current in said internal power source declines over time as said internal impedance of the said internal power source increases.