Power Converter Employing Integrated Magnetics with a Current Multiplier Rectifier and Method of Operating the Same

• US 20080310190A1
• Filed: 08/25/2008
• Published: 12/18/2008
• Est. Priority Date: 02/08/2005
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Original Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Inventors: Chandrasekaran, Sriram, Mehrotra, Vivek
• Granted Patent: US 7,675,764 B2
• Time in Patent Office: Days
• US Class Current: 363/17
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power converter having input and output nodes and a method of operating the same. In one embodiment, the power converter includes a switching circuit including first, second and third active phase legs. Each of the first, second and third active legs includes a first switch coupled to one of the input nodes and a second switch coupled to another of the input nodes and has a common switching node therebetween. The power converter further includes a magnetic device including first, second and third primary windings, and first, second and third secondary windings. The first, second and third primary windings are coupled to the common switching node of the first, second and third active phase legs, respectively. The power converter still further includes a rectifier including first, second and third rectifier elements interposed between the first, second and third secondary windings, respectively, and one of the output nodes.

Claims

1. A power converter having input and output nodes, comprising:

a switching circuit including first and second active phase legs, each of said first and second active phase legs having a first switch coupled to one of said input nodes and a second switch coupled to another of said input nodes and having a common switching node therebetween;

an integrated magnetic device, including;

a magnetic core having first and second outer legs and a common leg,

first and second primary windings formed about said first and second outer legs, respectively, a terminal of each of said first and second primary windings being coupled to said common switching node of said first and second active phase legs, respectively, and

first and second secondary windings formed about said first and second outer legs, respectively, wherein said integrated magnetic device integrates a two-phase transformer to provide galvanic isolation between said primary and secondary windings with two-phase coupled inductors; and

a rectifier including first and second rectifier elements interposed between said first and second secondary windings, respectively, and one of said output nodes.

2. The power converter as recited in claim 1 wherein another terminal of each of said first and second primary windings is coupled together at a common node.

3. The power converter as recited in claim 1 wherein said first and second switches are enabled to conduct in a complementary manner.

4. The power converter as recited in claim 1 wherein said first and second rectifier elements are interposed between a terminal of said first and second secondary windings and said one of said output nodes, and another terminal of said first and second secondary windings is coupled to another of said output nodes.

5. The power converter as recited in claim 1 wherein said first and second outer legs are along an outer edge of a base and said common leg spans said first and second outer legs along another outer edge of said base, said magnetic core having a top plate opposite said base that covers said first and second outer legs and said common leg.

6. The power converter as recited in claim 1 wherein said first and second outer legs and said common leg are located on a base and said magnetic core has a top plate opposite said base that covers said first and second outer legs and said common leg, with an air gap between said common leg and said top plate.

7. The power converter as recited in claim 1 wherein said first and second primary windings are encircled by said first and second secondary windings, respectively.

8. The power converter as recited in claim 1 wherein said first and second secondary windings include a tab configured to provide terminal connections therefor.

9. The power converter as recited in claim 1 wherein said first or second switch of said first active phase leg begins conducting substantially concurrently with said first rectifier element.

10. The power converter as recited in claim 1 further comprising another inductor coupled to said integrated magnetic device.

11. A method of operating a power converter having input nodes coupled to a source of electrical power and output nodes, comprising:

controlling a first switch coupled to one of said input nodes and a second switch coupled to another of said input nodes of a first active phase leg of a switching circuit to impress an input voltage from said source of electrical power across a first primary winding formed about a first outer leg of a magnetic core of an integrated magnetic device, a terminal of said first primary winding being coupled to a common switching node between said first and second switches of said first active phase leg;

controlling a first switch coupled to one of said input nodes and a second switch coupled to another of said input nodes of a second active phase leg of a switching circuit to impress an input voltage from said source of electrical power across a second primary winding formed about a second outer leg of said magnetic core of said integrated magnetic device, a terminal of said second primary winding being coupled to a common switching node between said first and second switches of said second active phase leg;

providing an output voltage at said output nodes via first and second rectifier elements of a rectifier coupled to first and second secondary windings, respectively, formed about said first and second outer legs, respectively, of said magnetic core of said integrated magnetic device, wherein said integrated magnetic device integrates a two-phase transformer to provide galvanic isolation between primary and secondary windings with two-phase coupled inductors.

12. The method as recited in claim 11 wherein another terminal of each of said first and second primary windings is coupled together at a common node.

13. The method as recited in claim 11 wherein said first and second switches are enabled to conduct in a complementary manner.

14. The method as recited in claim 11 wherein said first and second rectifier elements are interposed between a terminal of said first and second secondary windings and said one of said output nodes, and another terminal of said first and second secondary windings is coupled to another of said output nodes.

15. The method as recited in claim 11 wherein said first and second outer legs are along an outer edge of a base and said common leg spans said first and second outer legs along another outer edge of said base, said magnetic core having a top plate opposite said base that covers said first and second outer legs and said common leg.

16. The method as recited in claim 11 wherein said first and second outer legs and said common leg are located on a base and said magnetic core has a top plate opposite said base that covers said first and second outer legs and said common leg, with an air gap between said common leg and said top plate.

17. The method as recited in claim 11 wherein said first and second primary windings are encircled by said first and second secondary windings, respectively.

18. The method as recited in claim 11 wherein said first and second secondary windings include a tab configured to provide terminal connections therefor.

19. The method as recited in claim 11 wherein said first or second switch of said first active phase leg begins conducting substantially concurrently with said first rectifier element.

20. The method as recited in claim 11 further comprising supplementing an inductance of said integrated magnetic device.