Efficient External Charger for Charging a Plurality of Implantable Medical Devices

• US 20110121777A1
• Filed: 11/23/2009
• Published: 05/26/2011
• Est. Priority Date: 11/23/2009
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Shi, Jess, Ozawa, Robert, Carbunaru, Rafael, Chen, Joey, Parramon, Jordi, Rahman, Md. Mizanur
• Granted Patent: US 8,676,318 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

An improved external charger for a battery in an implantable medical device (implant), and technique for charging batteries in multiple implants using such improved external charger, is disclosed. During charging, values for a parameter measured in the implants are reported from the implants to the external charger. The external charger infers from the magnitudes of the parameters which of the implants has the highest and lowest coupling to the external charger, and so designates those implants as “hot” and “cold.” The intensity of the magnetic charging field is optimized for the cold implant consistent with the simulation to ensure that that the cold implant is charged with a maximum (fastest) battery charging current. The duty cycle of the magnetic charging field is also optimized for the hot implant consistent with the simulation to ensure that the hot implant does not exceed the power dissipation limit. As a result, charging is optimized to be fast for all of the implants, while still safe from a tissue heating perspective.

Claims

1. A method for charging batteries in a plurality of implantable medical devices, comprising:

(a) generating a magnetic charging field during a charging session using an external charger;

(b) measuring during the charging session at least one parameter in each of the implantable medical devices;

(c) telemetering during the charging session the at least one parameter for each of the implantable medical devices to the external charger; and

(d) adjusting during the charging session the magnetic charging field in accordance with at least some of the telemetered parameters to maximize a battery charging current in one implant while not exceeding a maximum power dissipation limit for any other of the implantable medical devices.

2. The method of claim 1, wherein the magnetic charging field induces a battery charging current in each of the implants, and wherein the at least one parameters are indicative of the battery charging current in each of the implantable medical devices.

3. The method of claim 1, wherein adjusting the magnetic charging field comprises adjusting its intensity or duty cycle, or its intensity and duty cycle.

4. The method of claim 1, wherein the at least one parameter comprises a voltage across circuitry in line with the battery charging current.

5. The method of claim 4, wherein the one implant whose battery charging current is maximized has a lowest coupling with the external charger.

6. The method of claim 1, wherein the magnetic charging field is duty cycled, and wherein the at least one parameter for each of the implantable medical devices are telemetered during off periods in the duty cycle.

7. The method of claim 1, further comprising:

(e) repeating steps (b) through (d) periodically during the charging session.

8. A method for charging batteries in a plurality of implantable medical devices, comprising:

(a) generating a magnetic charging field during a charging session using an external charger;

(b) measuring during the charging session at least one parameter in each of the implantable medical devices;

(c) telemetering during the charging session the at least one parameter for each of the implantable medical devices to the external charger; and

(d) determining a first implant of the plurality of implants having a highest coupling to the external charger, and a second implant of the plurality of implants having lowest coupling to the external charger;

(e) adjusting during the charging session (i) the intensity of the magnetic charging field in accordance with at least one parameter telemetered from the second implant, and (ii) the duty cycle of the magnetic charging field in accordance with at least one parameter telemetered from the first implant.

9. The method of claim 8, wherein the first and second implants are determined using at least one of the parameters telemetered from each of the implants.

10. The method of claim 8, wherein the magnetic charging field induces a battery charging current in each of the implants, and wherein the at least one parameters are indicative of the battery charging current in each of the implantable medical devices.

11. The method of claim 8, wherein the at least one parameter comprises a voltage across circuitry in line with a battery charging current.

12. The method of claim 8, wherein determining the first implant comprises determining an implant with the smallest of the at least one parameters, and wherein determining the second implant comprises determining a largest of the at least one parameters.

13. The method of claim 8, wherein determining the first and second implants comprises discluding any of the plurality of implants having a battery that is fully charged.

14. The method of claim 8, further comprising:

(f) repeating steps (b) through (e) periodically during the charging session.

15. A method for charging batteries in a plurality of implantable medical devices, comprising:

(a) generating a magnetic charging field during a charging session using an external charger;

(b) measuring during the charging session at least one parameter in each of the implantable medical devices;

(c) telemetering during the charging session the at least one parameter for each of the implantable medical devices to the external charger;

(d) determining a first implant of the plurality of implants having a highest coupling to the external charger, and a second implant of the plurality of implants having lowest coupling to the external charger; and

(e) adjusting the intensity and duty cycle during the charging session to maximize the speed of charging of the second implant while ensuring the first implant does not exceed a maximum power dissipation limit.

16. The method of claim 15, wherein the first and second implants are determined using at least one of the parameters telemetered from each of the implants.

17. The method of claim 15, wherein the magnetic charging field induces a battery charging current in each of the implants, and wherein the at least one parameters are indicative of the battery charging current in each of the implantable medical devices.

18. The method of claim 15, wherein the at least one parameter comprises a voltage across circuitry in line with a battery charging current.

19. The method of claim 15, wherein determining the first implant comprises determining an implant with the smallest of the at least one parameters, and wherein determining the second implant comprises determining a largest of the at least one parameters.

20. The method of claim 15, wherein determining the first and second implants comprises discluding any of the plurality of implants having a battery that is fully charged.

21. The method of claim 15, further comprising:

(f) repeating steps (b) through (e) periodically during the charging session.

22. A method for charging batteries in a plurality of implantable medical devices, comprising:

(a) generating a magnetic charging field during a charging session using an external charger;

(b) measuring during the charging session at least one parameter in each of the implantable medical devices;

(c) telemetering during the charging session the at least one parameter for each of the implantable medical devices to the external charger;

(d) comparing at least some of the telemetered parameters to data stored in the external charger; and

(e) based on the comparison, adjusting during the charging session the magnetic charging field in accordance with at least some of the telemetered parameters to maximize charging speed in one implant while not exceeding a maximum power dissipation limit for any other of the implantable medical devices.

23. The method of claim 22, wherein the magnetic charging field induces a battery charging current in each of the implants, and wherein the at least one parameters are indicative of the battery charging current in each of the implantable medical devices.

24. The method of claim 22, wherein adjusting the magnetic charging field comprises adjusting its intensity or duty cycle, or its intensity and duty cycle.

25. The method of claim 22, wherein the at least one parameter comprises a voltage across circuitry in line with the battery charging current.

26. The method of claim 25, wherein the one implant whose charging speed is maximized has a lowest coupling with the external charger.

27. The method of claim 22, wherein the magnetic charging field is duty cycled, and wherein the at least one parameter for each of the implantable medical devices are telemetered during off periods in the duty cycle.

28. The method of claim 22, further comprising:

(f) repeating steps (b) through (e) periodically during the charging session.

29. A method for charging batteries in a plurality of implantable medical devices, comprising:

(a) generating a charging field during a charging session using an external charger to simultaneously charge the batteries in the implantable medical devices;

(b) monitoring at the external charger parameters indicative of the coupling between the external charger and each of the implantable medical devices during the charging session; and

(c) adjusting during the charging session the charging field in accordance with the parameters.

30. The method of claim 29, wherein the charging field is adjusted to optimize the speed with which the batteries in each of the implantable medical devices are charged.

31. The method of claim 30, wherein the charging field is adjusted to maximize a charging speed in one implant while not overheating any other of the implantable medical devices.

32. The method of claim 31, wherein the charging speed is maximized in the one implant by maximizing a battery charging current induced by the charging field in that one implant.

33. The method of claim 30, wherein the one implant whose battery charging current is maximized has a lowest coupling with the external charger.

34. The method of claim 29, wherein the parameters are further indicative of the battery charging current in each of the implantable medical devices.

35. The method of claim 29, wherein adjusting the charging field comprises adjusting its intensity or duty cycle, or its intensity and duty cycle.

36. The method of claim 29, wherein monitoring the parameters at the external charger comprises receiving the parameters by telemetry from the implantable medical devices.

37. The method of claim 29, further comprising:

(d) repeating steps (b) through (c) periodically during the charging session.