External charger with customizable magnetic charging field

• US 9,700,730 B2
• Filed: 05/03/2011
• Issued: 07/11/2017
• Est. Priority Date: 05/07/2010
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: DiGiore, Andrew, Carbunaru, Rafael, Whitehurst, Todd
• Primary Examiner(s): Wehrheim, Lindsey G
• Application Number:
  US13/099,906
• Publication Number:
  US 20110276111A1
• Time in Patent Office: 2,261 Days
• Field of Search: 607 33, 607 61
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

Improved external chargers for charging an implantable medical device, and particularly useful in charging a plurality of such devices, are disclosed. Each of the various embodiments include a plurality of field customization coils for customizing the magnetic charging field generated by the external charger such that the magnetic charging field is not radially symmetric. For example, one embodiment includes a primary coil with a plurality of field customization coils distributed radially with respect to the coil. The generated magnetic charging field can be rendered radially asymmetric by selectively activating or disabling the field customization coils in response to data quantifying the coupling between the various implants and the field customization coils in the charger. If there is a relatively high coupling between a particular implant and a particular customization coil for example, that customization coil can be activated to counter the magnetic charging field at that location, while still maintaining a relatively high magnetic charging field at the location of other implants that may have lower couplings.

Claims

1. An external charger for charging at least one implantable medical device, comprising:

a primary charging coil positioned radially symmetrically with respect to a main axis; and

a plurality of first coils that are positioned with radial symmetry with respect to the main axis, wherein each first coil is positioned at a different location about the main axis, and

wherein each of the first coils is configured to be differently activated in conjunction with activation of the primary charging coil to produce a combined magnetic field to charge the at least one implantable medical device, wherein the combined magnetic field is radially asymmetric with respect to the main axis.

2. The external charger of claim 1, wherein the plurality of first coils are located within an area extent of the primary charging coil.

3. The external charger of claim 1, further comprising a memory for storing a plurality of coupling parameters, and wherein each of the first coils is configured to be differently activated in accordance with at least one of the coupling parameters.

4. The external charger of claim 3, wherein each coupling parameter is indicative of the coupling between the external charger and one of the implantable medical devices.

5. The external charger of claim 4, wherein each coupling parameter is indicative of the coupling between one of the first coils and one of the plurality of implantable medical devices.

6. The external charger of claim 3, wherein each coupling parameter is indicative of the coupling between one of the first coils and at least one of the implantable medical devices.

7. The external charger of claim 1, wherein each of the first coils is configured to be differently activated by being controllable to carry different currents.

8. The external charger of claim 1, wherein each of the first coils is configured to be differently activated by being coupleable in series with the primary charging coil.

9. The external charger of claim 1, wherein each of the first coils is configured to be differently activated by being selectively openable or closeable.

10. The external charger of claim 1, wherein the first coils and the primary charging coil are comprised of separate wires.

11. The external charger of claim 1, wherein each of the first coils is coupled to at least one of a plurality of adjustable resistors, and wherein each of the first coils is configured to be differently activated by adjusting resistances of at least one of the adjustable resistors.

12. The external charger of claim 1, wherein each of the first coils is activated by a current source, and wherein each of the first coils is configured to be differently activated by setting the current sources.

13. The external charger of claim 1, wherein the primary charging coil is activated by a first current, and wherein at least one of the first coils is activated with a second current flowing in the opposite direction from the first current.

14. The external charger of claim 1, further comprising a test current source configured to provide a test current to each of the first coils to determine at least one coupling parameter between each first coil and at least one implantable medical device, and wherein each first coil is configured to be differently activated in accordance with its at least one coupling parameter.

15. An external charger for charging at least one implantable medical device, comprising:

a plurality of coplanar first coils positioned radially symmetrically with respect to a main axis, wherein each first coil is positioned at a different location about the main axis; and

test circuitry configured to determine at least one coupling parameter between each first coil and at least one implantable medical device,

wherein each of the first coils is configured to be differently activated in accordance with its at least one coupling parameter to produce a magnetic field that is radially asymmetric with respect to the main axis.

16. The external charger of claim 15, further comprising a memory for storing the coupling parameters.

17. The external charger of claim 15, wherein each of the first coils is configured to be differently activated by being controllable to carry different currents.

18. The external charger of claim 15, wherein each of the first coils is configured to be differently activated by being selectively openable or closeable.

19. The external charger of claim 15, wherein the first coils are comprised of separate wires.

20. The external charger of claim 15, wherein each of the first coils is coupled to at least one of a plurality of adjustable resistors, and wherein each of the first coils is configured to be differently activated by adjusting resistances of at least one of the adjustable resistors.

21. The external charger of claim 15, wherein each of the first coils is activated by a current source, and wherein each of the first coils is configured to be differently activated by setting the current sources in accordance with the at least one coupling parameter.

22. The external charger of claim 15, wherein the test circuitry comprises a test current source configured to provide a test current to each of the first coils to determine the coupling parameters.

23. The external charger of claim 15, further comprising a primary charging coil, wherein each of the first coils is configured to be differently activated in conjunction with activation of the primary coil to produce the magnetic field that is radially asymmetric with respect to the main axis.

24. The external charger of claim 23, wherein the main axis comprises a main axis of the primary charging coil.

25. The external charger of claim 23, wherein the plurality of first coils are located within an area extent of the primary charging coil.

26. The external charger of claim 23, wherein the primary charging coil is activated by a first current, and wherein at least one of the first coils is activated with a second current flowing in the opposite direction from the first current.

27. The external charger of claim 23, wherein each of the first coils is configured to be differently activated by being coupleable in series with the primary charging coil.