PLANAR PRINTED-CIRCUIT-BOARD TRANSFORMERS WITH EFFECTIVE ELECTROMAGNETIC INTERFERENCE (EMI) SHIELDING

• US 20030020583A1
• Filed: 06/15/2001
• Published: 01/30/2003
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Hui, Ron Shu Yuen, Tang, Sai Chun
• Granted Patent: US 6,501,364 B1
• Time in Patent Office: Days
• US Class Current: 336/200
• CPC Class Codes: H01F 27/2804 Printed windings
• 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

Abstract

Novel designs for printed circuit board transformers, and in particular for coreless printed circuit board transformers designed for operation in power transfer applications, are disclosed in which shielding is provided by a combination of ferrite plates and thin copper sheets.

Claims

1. A planar printed circuit board transformer comprising at least one copper sheet for electromagnetic shielding.

2. A planar printed circuit board transformer comprising,

(e) a printed circuit board,

(f) primary and secondary windings formed by coils deposited on opposed sides of said printed circuit board,

(g) first and second ferrite plates located over said primary and secondary windings respectively, and

(h) first and second copper sheets located over said first and second ferrite plates respectively.

3. A transformer as claimed in claim 2 wherein a thermally conductive insulating layer is located between each said winding and its associated said ferrite plate.