INDUCTIVELY RECHARGEABLE EXTERNAL ENERGY SOURCE, CHARGER, SYSTEM AND METHOD FOR A TRANSCUTANEOUS INDUCTIVE CHARGER FOR AN IMPLANTABLE MEDICAL DEVICE

• US 20100076524A1
• Filed: 10/28/2009
• Published: 03/25/2010
• Est. Priority Date: 10/02/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Phillips, William C., Forsberg, John W., Olson, David P., Schmeling, Andrew L.
• Granted Patent: US 8,005,547 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61M 2205/3327 Measuring
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2205/8237 Charging means
• CPC Class Codes: A61M 2209/01 Remote controllers for specific apparatus
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: A61N 1/3655 controlled by body or blood temperature
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/007192 in response to temperature

Abstract

A mechanism for transferring energy from an external power source to an implantable medical device is disclosed. An antenna is positioned in proximity of the implantable medical device. The position of a core of the antenna is adjusted relative to the implantable medical device while the antenna is maintained substantially stationary. A frequency of transmission of a power source is adjusted, and the antenna is driven at the adjusted frequency to transfer energy transcutaneously to the implantable medical device. In one embodiment, the frequency of transmission is selected based on an amplitude of a signal in the antenna.

Claims

1. A method of transcutaneously transferring energy from an external power source to an implantable medical device, comprising:

positioning an antenna in proximity of the implantable medical device;

laterally adjusting a position of a core of the antenna relative to the implantable medical device while the antenna is maintained substantially stationary;

adjusting a frequency of transmission of a power source; and

driving the antenna with the power source at the adjusted frequency to transfer energy transcutaneously to the implantable medical device.

2. The method of claim 1, wherein laterally adjusting the position of the core comprises positioning the core relative to a primary coil of the antenna.

3. The method of claim 2, wherein laterally adjusting the position of the core comprises positioning the core in any selected one of a plurality of predetermined positions relative to the primary coil.

4. The method of claim 1, wherein the core is a ferrite core.

5. The method of claim 1, wherein adjusting the frequency of transmission of the power source comprises selecting a frequency that optimizes impedance of a tuned inductive circuit comprising a primary coil of the antenna and a secondary coil of the implantable medical device.

6. The method of claim 1, wherein adjusting the frequency of transmission of the power source comprises:

varying frequency at which a primary coil of the antenna is driven by a transmitter of the power source; and

determining a frequency at which amplitude of a signal in the primary coil is optimized.

7. The method of claim 1, wherein adjusting the frequency of transmission of the power source occurs while the power source drives the antenna to transfer energy to the implantable medical device.

8. The method of claim 1, further comprising limiting temperature of a surface of the antenna that is closest to the implantable medical device to a predetermined maximum temperature.

9. The method of claim 8, wherein limiting temperature of the surface of the antenna comprises sensing temperature with a temperature sensor.

10. The method of claim 1, wherein laterally adjusting a position of a core of the antenna comprises laterally adjusting a position of a ferrite core with respect to a secondary coil of the implantable medical device;

and

wherein adjusting a frequency of transmission of a power source comprises adjusting impedance of a tuned inductive circuit comprising a primary coil of the antenna and the secondary coil.

11. A system, comprising:

an implantable medical device operationally coupled to receive energy from a secondary coil;

an antenna adapted to be positioned at a selected location relative to the secondary coil;

an external power source coupled to generate a signal in the antenna at any selected frequency that is within a predetermined frequency range to transcutaneously transfer energy from the antenna to the secondary coil when the implantable medical device is implanted in a patient; and

a core selectably positionable relative to the antenna to focus the energy while the antenna is in the selected location.

12. The system of claim 11, further comprising a bracket adapted to be substantially centered relative to the implantable medical device, the bracket being removably coupled to the antenna to maintain the antenna at the selected position.

13. The system of claim 12, wherein the bracket has an opening adapted to be substantially centered relative to the implantable medical device using palpatory sensation.

14. The system of claim 11, wherein the antenna comprises a primary coil and wherein the core is positioned within the primary coil to focus magnetic flux generated by the primary coil.

15. The system of claim 14, wherein the core is rotatably positionable within the primary coil at any selected one of multiple predetermined positions.

16. The system of claim 11, wherein the antenna further comprises a core cup assembly adapted to support the core.

17. The system of claim 11, wherein the external power source further comprises a circuit to generate the signal at a frequency at which an amplitude of the signal is optimized.

18. The system of claim 11, wherein the antenna and the external power source are contained within a same housing.

19. The system of claim 11, wherein the antenna further comprises:

a thermally-conductive surface adapted to contact a patient; and

a temperature sensor to determine a temperature of the thermally-conductive surface.

20. The system of claim 11, wherein the antenna further comprises:

a temperature sensor; and

control circuitry communicatively coupled to the temperature sensor and adapted to limit a temperature of a surface of the antenna to which a patient comes in contact.

21. A system to transcutaneously transfer power to an implantable medical device, comprising:

an antenna adapted to be positioned at a selected location relative to the implantable medical device;

an adjustable power source coupled to drive the antenna at a selected frequency that is selected to increase efficiency of energy transfer from the antenna to the implantable medical device; and

a core movably coupled to the antenna and adapted to be laterally positionable relative to the implantable medical device while the antenna is maintained at the selected location, the core to focus the energy transferred from the antenna to the implantable medical device in a selectable manner.

22. The system of claim 21, further comprising a circuit to vary a frequency at which the antenna is driven to allow the selected frequency to be chosen.

23. The system of claim 22, wherein the circuit varies the frequency at which the antenna is driven while energy is transferred from the antenna to the implantable medical device.

24. The system of claim 21, wherein the selected frequency is chosen based on an amplitude of a signal in the antenna.

25. The system of claim 21, further including a primary coil surrounding the core, and wherein the core is laterally positionable with respect to the primary coil.

26. The system of claim 21, further comprising a temperature sensor to measure a temperature of the antenna, and wherein the adjustable power source comprises control circuitry to limit the energy transferred from the antenna to the implantable medical device based on the temperature.

27. A system, comprising:

an implantable medical device for providing a therapy to a patient, the implantable medical device having a secondary coil and a rechargeable power source;

an external charging system, comprising;

primary coil;

a variable power source adapted to generate a signal in the primary coil that is of a selectable frequency chosen to optimize an amplitude of the signal; and

a moveable core positionable relative to the primary coil and to the secondary coil and adapted to focus magnetic flux generated by the signal in the primary coil, whereby efficiency of energy transfer between the external charging system and the implantable medical device is increased.

28. The system of claim 27, wherein the generated signals are in a frequency range of between eight and twelve kilohertz.