Vertical winding structures for planar magnetic switched-mode power converters

• US 20060038650A1
• Filed: 08/19/2004
• Published: 02/23/2006
• Est. Priority Date: 08/19/2004
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.), MyPAQ Holdings Ltd. (Transpacific IP Group Limited)
• Original Assignee: Rockwell Scientific Licensing LLC
• Inventors: Sun, Jian, Chandrasekaran, Sriram, Mehrotra, Vivek
• Granted Patent: US 7,321,283 B2
• Time in Patent Office: Days
• US Class Current: 336/83
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H02M 3/28 using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac

Abstract

A vertical winding structure for planar integrated magnetics used in switched-mode power converters maintains close coupling between the different windings but reduces the eddy current losses, lowers the DC winding resistance and reduces the number of layers of the PCB. Vertical and horizontal windings can be used together without sacrificing these performance advantages and further minimizing the capacitive coupling between the outer-leg windings and the center-leg winding. This winding structure can be used in a wide range of magnetic structures including isolated and non-isolated CDRs, interleaved CDRs, and buck and boost converters.

Claims

1. A power converter, comprising:

a magnetic core having a base, first, center and second legs on the base, and a plate opposite the base; and

a vertical winding around at least one of said first, second and center legs

2. The power converter of claim 1, wherein the vertical winding is approximately orthogonal to said base and said plate and approximately parallel to the leg around which it is wound.

3. The power converter of claim 1, wherein the vertical winding is around the center leg.

4. The power converter of claim 3, wherein the vertical winding makes a single physical and magnetic turn.

5. The power converter of claim 3, further comprising:

a first winding around the first leg; and

a second winding around the second leg.

6. The power converter of claim 5, wherein said first, and second windings are horizontal windings.

7. The power converter of claim 6, wherein said first, and second horizontal windings comprise metal traces formed on a multi-layered printed circuit board (PCB).

8. The power converter of claim 7, further comprising a third horizontal winding around the first leg and a fourth horizontal winding around the second leg.

9. The power converter of claim 7, wherein the vertical winding is thicker than metal traces that form the horizontal windings.

10. The power converter of claim 5, wherein said first, and second windings are vertical windings.

11. The power converter of claim 10, further comprising third and fourth vertical windings around said first and second legs, respectively, said first and third vertical windings and said second and fourth vertical windings being formed one inside the other around each said leg and connected to define closely coupled split-primary windings and secondary windings.

12. The power converter of claim 11, wherein said first and third vertical windings and said second and fourth vertical windings each form multiple physical turns, said first and third winding turns each being connected in series to define a multiple magnetic turn split-primary winding, said second and fourth windings turn each being connected in series to define a single magnetic turn secondary winding with reduced resistance.

13. The power converter of claim 3, wherein a leakage field in a window area of the magnetic core is approximately horizontal near the top of the center leg towards the plate and approximately vertical moving away therefrom, said vertical winding being spaced away from said center leg and lowered with respect to said plate to reduce interaction of the vertical winding with the horizontal leakage field and be approximately aligned with the vertical leakage field.

14. The power converter of claim 13, wherein said magnetic core comprises either an air gap between said center leg and said plate or a material discontinuity at their interface that creates the horizontal leakage field.

15. The power converter of claim 3, wherein the magnetic core is an E-I core.

16. The power converter of claim 3, further comprising third and fourth legs, said first, second, third and fourth legs disposed at opposite corners of a rectangular base to define windows therebetween, said center leg disposed at the center of the rectangular base and extending in a plus shape into said windows and separated from said first, second, third and fourth legs, said plate disposed on said first, second, third and fourth legs.

17. The power converter of claim 16, wherein an air gap is formed between the center leg and the plate.

18. The power converter of claim 16, wherein the plate is disposed on the center leg, a portion of the center leg being formed of a high saturation flux density material.

19. The power converter of claim 3, further comprising a third leg, said first, second and third legs separated along a first outer edge of the base to define first and second windows therebetween, said center leg disposed along a second outer edge of the base and separated from said first, second and third legs to define a center window, said plate disposed on said first, second and third legs.

20. A power converter, comprising:

a multi-layer printed circuit board (PCB) having first, center and second holes formed therethrough, said PCB having a split-primary and secondary windings formed horizontally thereon around said first and second holes;

a magnetic core having a base below the PCB, first, center and second legs on the base and extending through the respective holes in the PCB so that the split-primary and secondary windings are wound around said first and second legs, and a plate above the PCB on said first and second legs; and

a vertical inductor winding around the center leg.

21. The power converter of claim 20, wherein the vertical winding is approximately orthogonal to said base and said plate and approximately parallel to the center leg.

22. The power converter of claim 20, wherein the vertical winding makes a single physical and magnetic turn.

23. The power converter of claim 20, wherein said vertical winding comprises a winding termination on the PCB.

24. The power converter of claim 20, wherein the vertical winding is thicker than the horizontal windings.

25. A power converter, comprising:

a matrix integrated magnetic (MIM) core having a base, first, second, third and center legs on the base, and a plate opposite the base; and

a vertical winding around at least one of said first, second, third and center legs.

26. The power converter of claim 25, wherein the vertical winding is around the center leg.

27. The power converter of claim 25, further comprising a fourth leg, said first, second, third and fourth legs disposed at opposite corners of a rectangular base to define windows therebetween, said center leg disposed at the center of the rectangular base and extending in a plus shape into said windows and separated from said first, second, third and fourth legs, said plate disposed on said first, second, third and fourth legs.

28. The power converter of claim 25, wherein said first, second and third legs separated along a first outer edge of the base to define first and second windows therebetween, said center leg disposed along a second outer edge of the base and separated from said first, second and third legs to define a center window, said plate disposed on said first, second and third legs.

29. The power converter of claim 25, wherein an air gap is formed between the center leg and the plate.

30. The power converter of claim 25, wherein the plate is disposed on the center leg, a portion of the center leg being formed of a high saturation flux density material.