Power converter employing a tapped inductor and integrated magnetics and method of operating the same

• US 7,298,118 B2
• Filed: 01/19/2007
• Issued: 11/20/2007
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Original Assignee: ColdWatt, Inc. (Flex, Ltd.)
• Inventors: Chandrasekaran, Sriram
• Primary Examiner(s): Vu; Bao Q.
• Application Number:
  US11/655,334
• Publication Number:
  US 20070114979A1
• Time in Patent Office: 305 Days
• Field of Search: 323/222, 323/282, 323/284, 323/285
• US Class Current: 323/222
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• 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 employing a tapped inductor and method of operating the same. In one embodiment, the power converter includes first and second tapped inductors including a tapped winding having a first section and a second section with a tap therebetween. The power converter also includes first and second active phase legs including a main switch series-coupled with an input node of the power converter and the first section of the tapped windings of the first and second tapped inductors, respectively. The first and second active phase legs also include an auxiliary switch interposed between the second section of the tapped windings of the first and second tapped inductors, respectively, and an output node of the power converter.

Claims

1. A power converter, comprising:

a magnetic device including a magnetic core with first and second tapped windings having first and second winding sections, respectively, coupled thereto; and

first and second active phase legs including a main switch and an auxiliary switch, respectively, said main switch of said first and second active phase legs being series-coupled with an input node of said power converter and said first winding section of said first and second tapped windings, respectively, said auxiliary switch of said first and second active phase legs being interposed between said second winding section of said first and second tapped windings, respectively, and an output node of said power converter.

2. The power converter as recited in claim 1 wherein said auxiliary switch of at least one of said first and second active phase legs is selected from the group consisting of:

a metal-oxide semiconductor field-effect transistor; and

a diode.

3. The power converter as recited in claim 1 wherein said auxiliary switch of at least one of said first and second active phase legs operates as a synchronous rectifier for said power converter.

4. The power converter as recited in claim 1 wherein said main switch of said first active phase leg is interposed between said first and second winding sections of said first tapped winding.

5. The power converter as recited in claim 1 wherein said main and auxiliary switches of at least one of said first and second active phase legs conduct in a substantially complementary manner.

6. The power converter as recited in claim 1 wherein said magnetic device is a matrix integrated magnetic device.

7. The power converter as recited in claim 1 wherein said magnetic core includes a common leg with an air gap and at least one outer leg.

8. The power converter as recited in claim 1 wherein said magnetic core includes a common leg and a plurality of outer legs, said first and second winding sections of said first tapped winding being coupled pairs about a different one of said plurality of said outer legs.

9. The power converter as recited in claim 1 wherein a reluctance of a magnetic path coupling said first and second winding sections of said first tapped winding is less than a reluctance of a common magnetic flux return path thereof.

10. The power converter as recited in claim 1 wherein a duty cycle associated with said main and auxiliary switches of said second active phase leg is delayed from a duty cycle associated with said main and auxiliary switches of said first active phase leg substantially inversely proportional to a number of active phase legs of said power converter.

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

providing a magnetic device including a magnetic core with first and second tapped windings having first and second winding sections, respectively, coupled thereto; and

first and second active phase legs including a main switch and an auxiliary switch, respectively, said main switch of said first and second active phase legs being series-coupled with an input node of said power converter and said first winding section of said first and second tapped windings, respectively, said auxiliary switch of said first and second active phase legs being interposed between said second winding section of said first and second tapped windings, respectively, and an output node of said power converter.

12. The method as recited in claim 11 wherein said auxiliary switch of at least one of said first and second active phase legs is selected from the group consisting of:

a metal-oxide semiconductor field-effect transistor; and

a diode.

13. The method as recited in claim 11 wherein said auxiliary switch of at least one of said first and second active phase legs operates as a synchronous rectifier for said power converter.

14. The method as recited in claim 11 wherein said main switch of said first active phase leg is interposed between said first and second winding sections of said first tapped winding.

15. The method as recited in claim 11 wherein said main and auxiliary switches of at least one of said first and second active phase legs conduct in a substantially complementary manner.

16. The method as recited in claim 11 wherein said magnetic device is a matrix integrated magnetic device.

17. The method as recited in claim 11 wherein said magnetic core includes a common leg with an air gap and at least one outer leg.

18. The method as recited in claim 11 wherein said magnetic core includes a common leg and a plurality of outer legs, said first and second winding sections of said first tapped winding being coupled pairs about a different one of said plurality of said outer legs.

19. The method as recited in claim 11 wherein a reluctance of a magnetic path coupling said first and second winding sections of said first tapped winding is less than a reluctance of a common magnetic flux return path thereof.

20. The method as recited in claim 11 wherein a duty cycle associated with said main and auxiliary switches of said second active phase leg is delayed from a duty cycle associated with said main and auxiliary switches of said first active phase leg substantially inversely proportional to a number of active phase legs of said power converter.