Inductive charger with magnetic shielding

Patent metadata

Field	Value
Publication number	US-9636508-B2
Application number	US-201514696866-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Mar 26, 2010
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

To recharge an implanted medical device, an external device, typically in the form of an inductive charger, is placed over the implant to provide for transcutaneous energy transfer. The external charging device can be powered by a rechargeable battery. Since the battery is in close proximity to the charge coil, the large magnetic field produced by the charge coil induces eddy currents that flow on the battery's metallic case, often resulting in undesirable heating of the battery and reduced efficiency of the charger. This disclosure provides a means of shielding the battery from the magnetic field to reduce eddy current heating, thereby increasing efficiency. In one embodiment, the magnetic shield consists of one or more thin ferrite plates. The use of a ferrite shield allows the battery to be placed directly over the charge coil as opposed to outside the extent of the charge coil.

First claim

What is claimed is:

1. An external device for use with an implantable medical device, comprising:
a housing;
a coil within the housing;
a battery within the housing; and
a magnetic shield within the housing comprising a high permeability material; and
a printed circuit board (PCB) within the housing of the external device, wherein the magnetic shield and coil are located on a first side of the PCB, and the battery is located on a second side of the PCB,
wherein the coil, the magnetic shield, and the battery are co-axially aligned in a stack, wherein the magnetic shield is located between the battery and the coil in the stack, and
wherein the coil generates a magnetic field to provide power to the implantable medical device.

2. The device of claim 1 , wherein the magnetic shield comprises a ferrite plate.

3. The device of claim 1 , wherein the battery comprises a rechargeable Lithium-ion battery.

4. The device of claim 1 , wherein the magnetic shield covers the entire extent of the coil.

5. The device of claim 1 , wherein the magnetic shield is adhesively attached to the PCB.

6. The device of claim 1 , wherein the magnetic shield comprises a plurality of plates.

7. The device of claim 6 , wherein each of the plurality of plates is a ferrite plate, and wherein the plurality of plates are configured in a tiled arrangement that covers the entire extent of the coil.

8. An external device for use with an implantable medical device, comprising:
a housing;
a coil within the housing;
a battery within the housing;
a magnetic shield within the housing made of a high permeability material, wherein the magnetic shield covers the battery; and
a printed circuit board (PCB) within the housing of the external device, wherein the PCB has a cutout area to accommodate the battery and magnetic shield,
wherein the magnetic shield and battery are within the extent of the coil, and
wherein the coil generates a magnetic field to provide power to the implantable medical device.

9. The device of claim 8 , wherein the magnetic shield comprises a box.

10. The device of claim 9 , wherein the box comprises two clamshell ferrite plates.

11. The device of claim 9 , wherein the box comprises a plurality of ferrite plates configured in a tiled arrangement that covers the entire battery.

12. The device of claim 8 , further comprising electronic circuitry, wherein the coil is located around an outer edge of a first side of the PCB, and the electronic circuitry is located on a second side of the PCB.

13. The device of claim 8 , wherein the magnetic shield contains gaps.

14. The device of claim 8 , wherein the coil, battery, and magnetic shield are co-axially aligned.

15. An external device for use with an implantable medical device, comprising:
a housing;
a coil within the housing;
a battery within the housing;
a magnetic shield within the housing comprising a high permeability material; and
a printed circuit board (PCB) within the housing of the external device, wherein the magnetic shield and battery are located on a first side of the PCB, and the coil is located on a second side of the PCB,
wherein the magnetic shield is located between the battery and the coil, and
wherein the coil generates a magnetic field to provide power to the implantable medical device.

16. The device of claim 15 , wherein the magnetic shield comprises a ferrite plate.

17. The device of claim 15 , wherein the coil, battery, and magnetic shield are co-axially aligned in a stack.

18. The device of claim 15 , wherein the magnetic shield is adhesively attached to the PCB.

19. The device of claim 15 , wherein the magnetic shield comprises a plurality of plates.

20. The device of claim 19 , wherein each of the plurality of plates is a ferrite plate, and wherein the plurality of plates are configured in a tiled arrangement that covers the entire extent of the coil.

Assignees

• Boston Scient Neuromodulation Corp

Inventors

• Chen Joey
• Ozawa Robert
• Aghassian Daniel

Classifications

• H02J50/70 Primary

  involving the reduction of electric, magnetic or electromagnetic leakage fields · CPC title

• H02J7/342

  The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging (with circuits for polarity protection H02J7/68) · CPC title

• H01F38/14

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• H02J50/10

  using inductive coupling · CPC title

• A61N1/3787

  from an external energy source · CPC title