Thermally enhanced magnetic transformer

• US 7,920,039 B2
• Filed: 09/25/2008
• Issued: 04/05/2011
• Est. Priority Date: 09/25/2007
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Aguayo, Juan, Rao, Srinivas, Shabany, Younes
• Primary Examiner(s): Mai; Anh T
• Assistant Examiner(s): Hinson; Ronald W
• Application Number:
  US12/284,934
• Publication Number:
  US 20090079528A1
• Time in Patent Office: 922 Days
• Field of Search: 336/60, 336/61, 336/200, 336/232
• US Class Current: 336/61
• CPC Class Codes: H01F 2027/2819 Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit
• CPC Class Codes: H01F 2027/297 with pin-like terminal to be inserted in hole of printed path
• CPC Class Codes: H01F 27/22 Cooling by heat conduction through solid or powdered fillings
• CPC Class Codes: H01F 41/0206 Manufacturing of magnetic cores by mechanical means magnetic cores per se H01F27/24
• CPC Class Codes: Y10T 29/49073 by assembling coil and core

Abstract

A planar transformer comprises a laminate substrate having an opening with metal traces wound thereabout forming a primary and a secondary winding, a core configured to fit inside the opening to enclose the laminate substrate. At least one heat sink fin is integrally formed with the top, bottom or both sides of the core. A method of forming a planar transformer comprises laminating a substrate having an opening with metal traces wound thereabout forming a primary and a secondary winding, fitting a core inside the opening, and enclosing the laminate substrate. One of the top, bottom or both sides of the core include one or more heat sink fins.

Claims

1. A planar transformer comprising:

a. a laminate substrate having an opening with metal traces wound thereabout forming a primary and a secondary winding;

b. a core having a top core configured to fit inside and surround the opening and a bottom core to mount to the top core;

c. at least one heat sink fin, wherein the at least one heat sink fin is integrally formed on the top core; and

d. an uninterrupted and uniform heat conduction thermal path, wherein the thermal path extends from the top core to the at least one heat sink fin.

2. The planar transformer of claim 1 wherein the core comprises a ferrite ceramic.

3. The planar transformer of claim 1 wherein the core comprises iron.

4. The planar transformer of claim 1 wherein the core comprises a surface coating of a material having high thermal conductivity.

5. A planar transformer comprising:

a. a laminate substrate having an opening with metal traces wound thereabout forming a primary and a secondary winding;

b. a core having a top core configured to fit inside and surround the opening and a bottom core to mount to the top core;

c. at least one heat sink fin, wherein the at least one heat sink fin is integrally formed on the bottom core; and

d. an uninterrupted and uniform heat conduction thermal path, wherein the thermal path extends from the bottom core to the at least one heat sink fin.

6. The planar transformer of claim 5 wherein the core comprises a ferrite ceramic.

7. The planar transformer of claim 5 wherein the core comprises iron.

8. The planar transformer of claim 5 wherein the core comprises a surface coating of a material having high thermal conductivity.

9. The planar transformer of claim 5 further comprising at least one heat sink fin, wherein the at least one heat sink fin is integrally formed on the top core.

19. The planar transformer of claim 5, wherein the heat sink fin couples to a component containing PCB.

10. A method of forming a planar transformer comprising:

a. laminating a substrate having an opening with metal traces wound thereabout forming a primary and a secondary winding;

b. mounting a core to the transformer, the core having a top core configured to fit inside and surround the opening and a bottom core to mount to the top core, wherein the top core has at least one integrally formed heat sink fin; and

c. forming an uninterrupted and uniform heat conduction thermal path, wherein the thermal path extends from the top core to the at least one integrally formed heat sink fin.

11. The method of claim 10 wherein the core comprises a ferrite ceramic.

12. The method of claim 10 wherein the core comprises iron.

13. The method of claim 10 further comprising the step of coating a surface of the core with a material having high thermal conductivity.

20. The method of claim 10 further comprising forming the top core containing the at least one integrally formed heat sink fin in an extrusion process.

14. A method of forming a planar transformer comprising:

a. laminating a substrate having an opening with metal traces wound thereabout forming a primary and a secondary winding;

b. mounting a core to the transformer, the core having a top core configured to fit inside and surround the opening and a bottom core to mount to the top core, wherein the bottom core has at least one integrally formed heat sink fin; and

c. forming an uninterrupted and uniform heat conduction thermal path, wherein the thermal path extends from the bottom core to the at least one integrally formed heat sink fin.

15. The method of claim 14 wherein the core comprises a ferrite ceramic.

16. The method of claim 14 wherein the core comprises iron.

17. The planar transformer of claim 14 further comprising the step of coating a surface of the core with a material having high thermal conductivity.

18. The method of claim 14 further comprising at least one heat sink fin, wherein the at least one heat sink fin is integrally formed on the top core.

21. The method of claim 14 further comprising forming the bottom core containing the at least one integrally formed heat sink fin in an extrusion process.