CONCENTRIC PRIMARY COILS FOR INDUCTIVELY CHARGING AN IMPLANTABLE MEDICAL DEVICE, EXTERNAL POWER SOURCE AND METHOD

• US 20090276016A1
• Filed: 04/30/2008
• Published: 11/05/2009
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Phillips, William C., Olson, David P., Widman, Erik G.
• Granted Patent: US 8,229,567 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

An external antenna with a plurality of concentric primary coils recharges an implantable medical device with a secondary coil when the primary coils are placed in proximity of the secondary coil. Selection circuitry determines which of the plurality of concentric primary coils has the most efficient coupling with the secondary coil and drive circuitry drives the selected primary coil with an oscillating current. During a recharge session, selection circuitry periodically checks at least some of the primary coils to determine whether the primary coil with the most efficient connection has changed. An antenna housing may hold the primary coils in a rigid planar relationship with each other or the primary coils may shift with respect to each other, forming a cup-shape around a bulge in the skin created by the implantable medical device.

Claims

1. An external power source for an implantable medical device having therapeutic componentry and a secondary coil operatively coupled to said therapeutic componentry, comprising:

a plurality of concentric primary charging coils, each capable of transcutaneously inductively energizing said secondary coil when externally placed in proximity of said secondary coil; and

drive circuitry selectively coupled to each of said plurality of concentric primary coils for energizing a selected one of said plurality of concentric primary coils.

2. The external power source as in claim 1 wherein said selected one of said plurality of concentric primary coils is a single selected one of said plurality of concentric primary coils.

3. The external power source as in claim 1 wherein said selected one of said plurality of concentric primary coils is determined by efficiency of energy transfer.

4. The external power source as in claim 3 wherein said selected one of said plurality of concentric primary coils is determined to be one of said plurality of concentric primary coils providing a greatest efficiency of energy transfer between said selected one of said plurality of concentric primary coils and said secondary coil.

5. The external power source as in claim 1 further comprising selection circuitry operatively coupled to drive circuitry, said selection circuitry determining which of said plurality of concentric primary coils is selected to be said selected one of said plurality of concentric primary coils.

6. The external power source as in claim 5 wherein said selection circuitry determines said selected one of said plurality of concentric primary coils based on which of said plurality of concentric primary coils provides a greatest efficiency of energy transfer between said selected one of said plurality of concentric primary coils and said secondary coil.

7. The external power source as in claim 6 wherein said selection circuitry periodically determines an efficiency of energy transfer between each of said plurality of primary coils and said secondary coil.

8. The external power source as in claim 1 wherein each of said plurality of concentric primary coils has an inside diameter and an outside diameter, wherein said secondary coil has an outside diameter and wherein a distance between said outside diameter of one of said plurality of concentric primary coils to said inside diameter of a next larger one of said plurality of concentric primary coils is not greater than said outside diameter of said secondary coil.

9. The external power source as in claim 1 wherein said plurality of concentric primary coils lie in a plane.

10. The external power source as in claim 1 wherein a plane of one of said plurality of concentric primary coils is offset from a plane of another of said plurality of concentric primary coils whereby said plurality of concentric primary coils may more easily form over a bulge created by said implantable medical device than if said plurality of concentric primary coils were planar.

11. The external power source as in claim 1 wherein said implantable medical device further has a rechargeable power source operatively coupled to said secondary coil and wherein said selected one of said plurality of concentric primary coils charges said rechargeable power source.

12. A method of energizing a secondary coil of an implantable medical having therapeutic output componentry coupled to said secondary coil, comprising the steps of:

positioning an array of a plurality of concentric primary charging coils in proximity of said secondary coil, each of said plurality of concentric primary charging coils being capable of transcutaneously inductively energizing said secondary coil;

selecting a selected one of said plurality of concentric primary coils to be energized; and

energizing said selected one of said plurality of concentric primary coils.

13. The method as in claim 12 wherein said selecting step selects only a single one of said plurality of concentric primary coils.

14. The method as in claim 12 wherein said selecting step is determined, at least in part, by an efficiency of energy transfer between said plurality of concentric primary coils and said secondary coil.

15. The method as in claim 14 wherein said selecting step selects one of said plurality of concentric primary coils having a greatest efficiency of energy transfer with said secondary coil.

16. The method as in claim 15 wherein said selecting step periodically reselects one of said plurality of concentric primary coils.

17. The method as in claim 16 wherein said selecting step reselects one of said plurality of concentric primary coils at least once every minute.