Isolated power converter

• US 8,502,520 B2
• Filed: 12/22/2008
• Issued: 08/06/2013
• Est. Priority Date: 03/14/2007
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Original Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Inventors: Chandrasekaran, Sriram
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US12/341,804
• Publication Number:
  US 20090097290A1
• Time in Patent Office: 1,688 Days
• Field of Search: 336/170, 336/180, 336/182, 336/212, 336/214, 336/215, 336/216, 336/221, 336/222, 336/233, 323/250, 323/251, 323/262, 323/331, 323/332, 323/334, 323/355, 323/359, 323/362, 363/125, 363/126, 363/127, 363/89
• US Class Current: 323/362
• CPC Class Codes: H01F 27/38 Auxiliary core members; Auxiliary coils or windings
• CPC Class Codes: H01F 27/40 Structural association with built-in electric component, e.g. fuse
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H01F 37/00 Fixed inductances not covered by group H01F17/00
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

An isolated power converter that includes, in one embodiment, a first magnetic core having a primary winding and a secondary winding around the first magnetic core. The power converter includes a second magnetic core having a first leg, a second leg coupled to the first leg, and a third leg coupled to the first and second legs, wherein a part of the third leg is equidistant from the first leg and the second leg. The power converter also includes a first winding encircling the first leg, a first end of the first winding coupled to the secondary winding, a second winding encircling the second leg, a first end of the second winding coupled to the secondary winding, and a third winding encircling the third leg, a first end of the third winding coupled to a second end of the first winding and to a second end of the second winding.

Claims

1. A power converter, comprising:

a transformer including a transformer core with a plurality of legs; and

an inductor, coupled to the transformer, including;

an inductor core including first and second outer legs and a center leg,

first and second inductor windings wrapped around the first and second outer legs, respectively, and

a center inductor winding wrapped around the center leg and with a first end connected to the first and second inductor windings, the center leg having a part thereof equidistant from the first and second outer legs.

2. The power converter of claim 1 wherein a first end of the first and second inductor windings is coupled to a secondary winding wrapped around one of the plurality of legs of the transformer core, and the first end of the center inductor winding is connected to a second end of the first and second inductor windings.

3. The power converter of claim 1 further comprising a capacitor coupled to a second end of the center inductor winding.

4. The power converter of claim 2 further comprising a rectification component coupled to the first end of the first and second inductor windings.

5. The power converter of claim 4 wherein the rectification component is selected from the group consisting of:

a synchronous rectifier, and

a diode.

6. The power converter of claim 1 wherein the transformer includes a primary winding and a secondary winding wrapped around one of the plurality of legs of the transformer core.

7. The power converter of claim 1 wherein the center leg of the inductor has an air gap.

8. The power converter of claim 1 further comprising at least one switching device coupled to the transformer.

9. The power converter of claim 1 further comprising a plurality of switching devices forming a full bridge topology coupled to the transformer.

10. The power converter of claim 9 wherein the plurality of switching devices are configured to be controlled to produce a symmetrical quasi-square wave AC signal.

11. A method of manufacturing a power converter, comprising:

forming a transformer including a transformer core with a plurality of legs; and

forming an inductor, coupled to the transformer, including;

providing an inductor core including first and second outer legs and a center leg,

wrapping first and second inductor windings around the first and second outer legs, respectively, and

wrapping a center inductor winding around the center leg and with a first end connected to the first and second inductor windings, the center leg having a part thereof equidistant from the first and second outer legs.

12. The method of claim 11 wherein forming the inductor includes coupling a first end of the first and second inductor windings to a secondary winding wrapped around one of the plurality of legs of the transformer core, and connecting the first end of the center inductor winding to a second end of the first and second inductor windings.

13. The method of claim 11 further comprising coupling a capacitor to a second end of the center inductor winding.

14. The method of claim 12 further comprising coupling a rectification component to the first end of the first and second inductor windings.

15. The method of claim 14 wherein the rectification component is selected from the group consisting of:

a synchronous rectifier, and

a diode.

16. The method of claim 11 wherein forming the transformer includes wrapping a primary winding and a secondary winding around one of the plurality of legs of the transformer core.

17. The method of claim 11 wherein forming the inductor includes providing an air gap in the center leg thereof.

18. The method of claim 11 further comprising coupling at least one switching device to the transformer.

19. The method of claim 11 further comprising coupling a plurality of switching devices forming a full bridge topology to the transformer.

20. The method of claim 19 wherein the plurality of switching devices are configured to be controlled to produce a symmetrical quasi-square wave AC signal.