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

• US 7,876,191 B2
• Filed: 11/19/2007
• Issued: 01/25/2011
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Original Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Inventors: Zhang, Jun, Kao, Kris Y., Chandrasekaran, Sriram
• Primary Examiner(s): Mai; Anh T
• Assistant Examiner(s): BAISA, JOSELITO SASIS
• Application Number:
  US11/942,632
• Publication Number:
  US 20080150666A1
• Time in Patent Office: 1,163 Days
• Field of Search: 336/212
• US Class Current: 336/212
• CPC Class Codes: H01F 27/2847 Sheets; Strips H01F27/2866 takes precedence
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

A power converter employing a magnetic device including a magnetic core and first and second tapped windings. Each winding of the magnetic device has first and second winding sections, respectively, coupled to the magnetic core, wherein the first and second winding sections are formed from a formed and folded planar conductive sheet. The magnetic core includes a common leg, a plurality of outer legs, and a top plate. The first and second winding sections are constructed with a formed and folded planar conductive sheet formed with structures usable as pins in a through-hole, surface-mount, or combined printed wiring board assembly process. The outer legs at either end of the magnetic core are positioned back from magnetic core ends, and the magnetic core is formed with a stepped structure to accommodate winding pins in a surface-mount printed wiring board assembly process.

Claims

1. A power converter, comprising:

a magnetic device, including;

a magnetic core, including;

a common leg,

a plurality of outer legs, and

a top plate; and

first and second tapped windings each having first and second winding sections, respectively, coupled to said magnetic core, wherein said first and second winding sections are formed from a formed and folded planar conductive sheet; 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 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 coupled to 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 formed and folded planar conductive sheet is a copper sheet.

3. The power converter as recited in claim 1 wherein said first and second winding sections are constructed with a formed and folded planar conductive sheet formed with structures usable as pins in a through-hole printed wiring board assembly process.

4. The power converter as recited in claim 1 wherein said first and second winding sections are constructed with a formed and folded planar conductive sheet formed with structures usable as pins in a surface-mount printed wiring board assembly process.

5. The power converter as recited in claim 1 wherein said first and second winding sections are constructed with a formed and folded planar conductive sheet formed with structures usable as pins in a combined through-hole and surface-mount printed wiring board assembly process.

6. The power converter as recited in claim 1 wherein said magnetic core is formed with a stepped structure to accommodate winding pins in a surface-mount printed wiring board assembly process.

7. The power converter as recited in claim 1 wherein said top plate is formed with a stepped structure to accommodate winding pins in a through-hole printed wiring board assembly process.

8. The power converter as recited in claim 1 wherein said outer legs are longer than said common leg, and wherein a gap in a magnetic path is formed between said common leg and said top plate.

9. The power converter as recited in claim 1 wherein said outer legs at either end of said magnetic core are positioned back from magnetic core ends.

10. The power converter as recited in claim 1 wherein a combined cross-sectional area of said outer legs is substantially equal to a combined cross-sectional area of said common legs.

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

12. The power converter as recited in claim 1 wherein said magnetic device is a tapped inductor.

13. 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.

14. The power converter as recited in claim 1 wherein said main switch of at least one of said first and second active phase legs is a metal-oxide semiconductor field-effect transistor.

15. 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.

16. 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 of said first tapped winding.

17. 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.

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

19. 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.

20. 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 said 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.