Power converter employing regulators with a coupled inductor

• US 8,125,205 B2
• Filed: 08/30/2007
• Issued: 02/28/2012
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Original Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Inventors: Chandrasekaran, Sriram, Mayer, Raymond George
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US11/847,450
• Publication Number:
  US 20080054874A1
• Time in Patent Office: 1,643 Days
• Field of Search: 323/222, 323/262, 323/265, 323/272, 323/282
• US Class Current: 323/282
• CPC Class Codes: H01F 2038/026 non-linear inductive arrangements for converters, e.g. with additional windings
• CPC Class Codes: H01F 27/42 Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils circuits for controlling transformers, reactors or choke coils, for the purpose of obtaining a desired output H02P13/00; impedance networks H03H
• 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: H01F 38/02 for non-linear operation
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A power converter includes a power train with a coupled inductor and a plurality of regulators, and method of forming and operating the same. In one embodiment, the power train includes a coupled inductor including a magnetic core with a common leg, a first leg and a second leg. The coupled inductor also includes a common winding formed around the common leg, and first and second windings. The first winding is formed around the first leg, and is electrically and magnetically coupled to the common winding. The second winding is formed around the second leg, and is electrically and magnetically coupled to the common winding. The power train also includes a first regulator including a first main switch coupled to the first winding and a second regulator including a second main switch coupled to the second winding.

Claims

1. A power train for a power converter, comprising:

a coupled inductor, including;

a magnetic core with a common leg, a first leg and a second leg,

a common winding formed around said common leg and coupled between a first node and a second node,

a first winding formed around said first leg and coupled between said second node and a third node, and

a second winding formed around said second leg and coupled between said second node and a fourth node;

a first regulator including a first main switch having a non-control terminal coupled to said third node; and

a second regulator including a second main switch having a non-control terminal coupled to said fourth node.

2. The power train as recited in claim 1 wherein said first regulator includes a first diode.

3. The power train as recited in claim 1 wherein said first regulator includes a first diode coupled to said third node.

4. The power train as recited in claim 1 wherein said second regulator includes a second diode.

5. The power train as recited in claim 1 wherein said second regulator includes a second diode coupled to said fourth node.

6. The power train as recited in claim 1 wherein said first regulator includes a first diode and said second regulator includes a second diode.

7. The power train as recited in claim 1 wherein said first leg is a first outer leg and said second leg is a second outer leg.

8. The power train as recited in claim 1 further comprising an output filter capacitor coupled to said first regulator and said second regulator.

9. The power train as recited in claim 1 wherein said first winding and said second winding have an equal number of turns.

10. The power train as recited in claim 1 wherein said magnetic core includes a gap formed between an upper surface of said common leg and a lower surface of an upper cross-member of said magnetic core.

11. A method of forming a power train for a power converter, comprising:

forming a coupled inductor, including;

providing a magnetic core with a common leg, a first leg and a second leg,

forming a common winding around said common leg and coupled between a first node and a second node,

forming a first winding around said first leg and coupled between said second node and a third node, and

forming a second winding around said second leg and coupled between said second node and a fourth node;

coupling a non-control terminal of a first main switch of a first regulator to said third node; and

coupling a non-control terminal of a second main switch of a second regulator to said fourth node.

12. The method as recited in claim 11 further comprising coupling a first diode to said first main switch of said first regulator.

13. The method as recited in claim 11 further comprising coupling a first diode to said third node.

14. The method as recited in claim 11 further comprising coupling a second diode to said second main switch of said second regulator.

15. The method as recited in claim 11 further comprising coupling a second diode to said fourth node.

16. The method as recited in claim 11 further comprising coupling a first diode to said first main switch of said first regulator and coupling a second diode to said second main switch of said second regulator.

17. The method as recited in claim 11 wherein said first leg is a first outer leg and said second leg is a second outer leg.

18. The method as recited in claim 11 further comprising coupling an output filter capacitor to said first regulator and said second regulator.

19. The method as recited in claim 11 wherein said first winding and said second winding have an equal number of turns.

20. The method as recited in claim 11 further comprising forming a gap between an upper surface of said common leg and a lower surface of an upper cross-member of said magnetic core.

21. A power converter, comprising:

a power train for a power converter, including;

a coupled inductor, including;

a magnetic core with a common leg, a first leg and a second leg,

a common winding formed around said common leg and coupled between a first node and a second node,

a first winding formed around said first leg and coupled between said second node and a third node, and

a second winding formed around said second leg and coupled between said second node and a fourth node,

a first regulator including a first main switch having a non-control terminal coupled to said third node, and

a second regulator including a second main switch having a non-control terminal coupled to said fourth node; and

a controller configured control a duty cycle of said first main switch and said second main switch to regulate an output voltage of said power converter.

22. The power converter as recited in claim 21 wherein said first regulator includes a first diode coupled to said third node.

23. The power converter as recited in claim 21 wherein said second regulator includes a second diode coupled to said fourth node.

24. The power converter as recited in claim 21 wherein said duty cycle of said first and second main switches is less than 0.5.

25. The power converter as recited in claim 21 wherein said first regulator includes a first diode and said second regulator includes a second diode.

26. The power converter as recited in claim 21 wherein said first leg is a first outer leg and said second leg is a second outer leg.

27. The power converter as recited in claim 21 wherein said power train further includes an output filter capacitor coupled to said first regulator and said second regulator.

28. The power converter as recited in claim 21 wherein said first winding and said second winding have an equal number of turns.

29. The power converter as recited in claim 21 wherein said magnetic core includes a gap formed between an upper surface of said common leg and a lower surface of an upper cross-member of said magnetic core.

30. The power converter as recited in claim 21 further comprising a rectifier bridge coupled to said coupled inductor.

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

providing a coupled inductor, coupled to said input, including;

a magnetic core with a common leg, a first leg and a second leg,

a common winding formed around said common leg and coupled between a first node and a second node,

a first winding formed around said first leg and coupled between said second node and a third node, and

a second winding formed around said second leg and coupled between said second node and a fourth node, and

controlling a duty cycle of a first main switch, having a non-control terminal coupled to said third node, of a first regulator and a second main switch, having a non-control terminal coupled to said fourth node, of a second regulator to provide power transfer stages of said power converter.

32. The method as recited in claim 31 wherein said controlling provides a continuous conduction mode of operation for said power converter.

33. The method as recited in claim 31 wherein said power transfer stages include:

a first power transfer stage wherein said first main switch is conducting and said second main switch is non-conducting;

a second power transfer stage wherein said first main switch is non-conducting and said second main switch is conducting;

a third power transfer stage wherein said first and second main switches are conducting; and

a freewheeling power transfer stage wherein said first and second main switches are non-conducting.

34. The method as recited in claim 31 wherein said controlling includes controlling a first diode, coupled to said third node, of said first regulator and a second diode, coupled to said fourth node, of said second regulator.

35. The method as recited in claim 31 wherein said duty cycle of said first and second main switches is less than 0.5.

36. The method as recited in claim 31 wherein said first leg is a first outer leg and said second leg is a second outer leg.

37. The method as recited in claim 31 further comprising filtering an output voltage from said first regulator and said second regulator.

38. The method as recited in claim 31 wherein said first winding and said second winding have an equal number of turns.

39. The method as recited in claim 31 wherein said magnetic core includes a gap formed between an upper surface of said common leg and a lower surface of an upper cross-member of said magnetic core.

40. The method as recited in claim 31 further comprising a rectifying an input voltage of said power converter.