INDUCTIVE BATTERY CHARGER SYSTEM WITH PRIMARY TRANSFORMER WINDINGS FORMED IN A MULTI-LAYER STRUCTURE

• US 20070090790A1
• Filed: 12/14/2006
• Published: 04/26/2007
• Est. Priority Date: 06/10/2002
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: HUI, Shu-yuen
• Granted Patent: US 7,576,514 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 2017/008 Electric or magnetic shielding of printed inductances
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/361 made of combinations of electrically conductive material and ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction

Abstract

There is provided a planar inductive battery charging system designed to enable electronic devices to be recharged. The system includes a planar charging module having a charging surface on which a device to be recharged is placed. Within the charging module and parallel to the charging surface is at least one and preferably an array of primary windings that couple energy inductively to a secondary winding formed in the device to be recharged. The invention also provides secondary modules that allow the system to be used with conventional electronic devices not formed with secondary windings.

Claims

1. A battery powered portable electronic device comprising a rechargeable battery, and wherein said device includes a planar secondary winding for receiving electrical energy from a battery charger, and electromagnetic shielding between said winding and the major electronic components of said device, wherein said secondary winding lies in a plane parallel to a surface of said device adapted to be placed on a charging surface of a battery charging system.

2. An electronic device as claimed in claim 1 wherein said shielding comprises a sheet of ferrite material and a sheet of conductive material.

3. An electronic device as claimed in claim 1 wherein said winding is formed integrally with a back cover of said device.

4. A battery charging system comprising a primary module and at least one secondary module, said primary module comprising means for connecting to a mains supply, and at least one primary winding parallel to a charging surface of said primary module, and wherein said secondary module comprises a secondary winding parallel to a surface of said secondary module, circuit means for converting alternating current generated in said secondary winding to a regulated DC output, and a charging connector for connection to the charging socket of an electronic device.

5. A battery charging system as claimed in claim 4 wherein said primary charging module comprises a plurality of primary windings each associated with a respective charging surface whereby said primary charging module is able to receive a plurality of secondary charging modules simultaneously.

6. A battery charging system as claimed in claim 5 wherein said charging surfaces are provided with engagement means for engaging a secondary module.

7. A battery charging system as claimed in claim 6 wherein said engagement means include a mechanical switch whereby power is supplied to said primary winding only when a secondary module is engaged by a charging surface.

8. A battery charging system as claimed in claim 4 wherein said primary winding is formed by a coil.

9. A battery charging system as claimed in claim 8 wherein said coil is wound on a magnetic structure.

10. A battery charging system as claimed in claim 4 wherein said primary winding is printed in a printed circuit board.

11. A battery charging system as claimed in claim 4 wherein said secondary winding is formed by a coil.

12. A battery charging system as claimed in claim 4 wherein said secondary winding is printed on a printed circuit board.

13. A secondary module for a battery charging system, comprising:

a housing having at least one charging surface, a secondary winding provided in said housing parallel to said surface and adapted to receive magnetic flux when said surface is brought adjacent to a primary winding, circuit means for converting alternating current in said secondary winding to a regulated DC output, and a connector means for connecting said DC output to the charging socket of an electronic device.