Vertical Winding Structures for Planar Magnetic Switched-Mode Power Converters

• US 20080111657A1
• Filed: 01/16/2008
• Published: 05/15/2008
• Est. Priority Date: 08/19/2004
• Status: Active Grant

• Current Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Original Assignee: Flextronics International USA Incorporated (Flex, Ltd.)
• Inventors: Sun, Jian, Chandrasekaran, Sriram, Mehrotra, Vivek
• Granted Patent: US 7,554,430 B2
• Time in Patent Office: Days
• US Class Current: 336/178
• 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 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 said PCB, first, center and second legs on said base and extending through said respective holes in said PCB so that said split-primary and secondary windings are wound around said first and second legs, and a plate above said PCB on said first and second legs; and

a vertical inductor winding around said center leg.

2. The power converter as recited in claim 1 wherein said vertical inductor winding is approximately orthogonal to said base and said plate and approximately parallel to said center leg.

3. The power converter as recited in claim 1 wherein said vertical inductor winding makes a single physical and magnetic turn.

4. The power converter as recited in claim 1 wherein said vertical inductor winding comprises a winding termination on said PCB.

5. The power converter as recited in claim 1 wherein said vertical inductor winding is thicker than said split-primary and secondary windings.

6. A power converter, comprising:

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

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

7. The power converter as recited in claim 6 wherein said vertical winding is around said center leg.

8. The power converter as recited in claim 6 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 a center of said 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.

9. The power converter as recited in claim 6 wherein said first, second and third legs separated along a first outer edge of said base to define first and second windows therebetween, said center leg disposed along a second outer edge of said 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.

10. The power converter as recited in claim 6 wherein an air gap is formed between said center leg and said plate.

11. The power converter as recited in claim 6 wherein said plate is disposed on said center leg, a portion of said center leg being formed of a high saturation flux density material.