High frequency semiconductor transformer

• US 8,130,067 B2
• Filed: 05/11/2010
• Issued: 03/06/2012
• Est. Priority Date: 05/11/2010
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: Texas Instruments, Inc.
• Inventors: Lee, Dok Won, Smeys, Peter, Mohan, Anuraag, Hopper, Peter J.
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Baisa, Joselito
• Application Number:
  US12/777,654
• Publication Number:
  US 20110279214A1
• Time in Patent Office: 665 Days
• Field of Search: 336/200, 336/223, 336/232, 336/212, 336/213, 336/221, 324/249, 148/108, 148/311
• US Class Current: 336/200
• CPC Class Codes: H01F 17/08 Loading coils for telecommunication circuits
• CPC Class Codes: H01F 19/04 Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range resonant circuits H03H
• CPC Class Codes: H01F 27/2895 Windings disposed upon ring cores
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: H01F 5/003 Printed circuit coils
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

A semiconductor transformer provides high frequency operation by forming the primary windings of the transformer around a section of magnetic material that has a hard axis that lies substantially parallel to the direction of the magnetic field generated by the primary windings. The core can also be formed to have a number of sections where the magnetic flux follows the hard axis through each section of the core.

Claims

1. A transformer comprising:

a non-conductive structure;

a magnetic core structure including;

a first magnetic structure that touches the non-conductive structure, the first magnetic structure having a hard axis that lies in a first direction, and a bottom surface that lies in a horizontal plane;

a second magnetic structure that touches the non-conductive structure, the second magnetic structure having a hard axis that lies in a second direction different from the first direction, and a bottom surface; and

a third magnetic structure that touches the non-conductive structure, the third magnetic structure having a hard axis that lies in the first direction, and a bottom surface that lies in the horizontal plane, the first, second, and third magnetic structures being spaced apart from each other; and

a first coil that touches the non-conductive structure, the first coil being wrapped around the first magnetic structure so that magnetic field lines from the first coil extend along the hard axes of the first, second, and third magnetic structures.

2. The transformer of claim 1 wherein the bottom surface of the second magnetic structure lies above and spaced apart from the horizontal plane.

3. The transformer of claim 1 wherein the magnetic core structure further includes a fourth magnetic structure that touches the non-conductive structure, the fourth magnetic structure having a hard axis that lies in the second direction, and a bottom surface that lies above and spaced apart from the horizontal plane, the fourth magnetic structure being spaced apart from the first, second, and third magnetic structures, magnetic field lines from the first coil within the first, second, third, and fourth magnetic structures extending along substantially only the hard axes of the first, second, third, and fourth magnetic structures.

4. The transformer of claim 1 wherein the hard axes of the first and third magnetic structures are substantially parallel to a longitudinal axis of the first coil.

5. The transformer of claim 1 wherein magnetic field lines within the first, second, and third magnetic structures extend substantially only along the hard axes of the first, second, and third magnetic structures.

6. The transformer of claim 1 and further comprising a second coil that touches the non-conductive structure, the second coil being wrapped around only the third magnetic structure.

7. The transformer of claim 6 and further comprising a third coil that touches the non-conductive structure, the third coil being wrapped around only the second magnetic structure.

8. The transformer of claim 7:

wherein the magnetic core structure further includes a fourth magnetic structure that touches the non-conductive structure, the fourth magnetic structure having a hard axis that lies in the second direction, and being spaced apart from the first, second, and third magnetic structures, magnetic field lines within the first, second, third, and fourth magnetic structures extending along substantially only the hard axes of the first, second, third, and fourth magnetic structures; and

further comprising a fourth coil that touches the non-conductive structure, the fourth coil being wrapped around only the fourth magnetic structure.

9. A transformer comprising:

a non-conductive structure;

a magnetic core structure including;

a first magnetic structure that touches the non-conductive structure, the first magnetic structure having a hard axis that lies in a first direction; and

a second magnetic structure that touches the non-conductive structure, the second magnetic structure having a hard axis that lies in a second direction different from the first direction, the first and second magnetic structures being spaced apart from each other; and

a first coil that touches the non-conductive structure, the first coil being wrapped around only the first magnetic structure so that magnetic field lines from the first coil extend along the hard axes of the first and second magnetic structures.

10. The transformer of claim 9 wherein magnetic field lines within the first and second magnetic structures extend substantially only along the hard axes of the first and second magnetic structures.

11. The transformer of claim 9:

wherein the magnetic core structure further includes a third magnetic structure that touches the non-conductive structure, the third magnetic structure having a hard axis that lies in the first direction, the third magnetic structure being spaced apart from the first and second magnetic structures; and

further comprising a second coil that touches the non-conductive structure, the second coil being wrapped around only the third magnetic structure.

12. The transformer of claim 11 wherein the hard axes of the first and third magnetic structures are substantially parallel to a longitudinal axis of the first coil.

13. The transformer of claim 11 and further comprising a third coil that touches the non-conductive structure, the third coil being wrapped around the second magnetic structure.

14. The transformer of claim 13 wherein the magnetic core structure further includes a fourth magnetic structure that touches the non-conductive structure, the fourth magnetic structure having a hard axis that lies in the second direction, the fourth magnetic structure being spaced apart from the first, second, and third magnetic structures, magnetic field lines from the first coil within the first, second, third, and fourth magnetic structures extending along substantially only the hard axes of the first, second, third, and fourth magnetic structures;

and

further comprising a fourth coil that touches the non-conductive structure, the fourth coil being wrapped around only the fourth magnetic structure.

15. The transformer of claim 9 and further comprising:

a first die having a first substrate and a first metal interconnect structure that touches the first substrate and the non-conductive structure; and

a second die having;

a second substrate;

a second metal interconnect structure that touches the second substrate;

a non-conductive member that touches the second metal interconnect structure;

a magnetic core structure including;

a third magnetic structure that touches the non-conductive member, the third magnetic structure having a hard axis that lies in the first direction; and

a fourth magnetic structure that touches the non-conductive member, the fourth magnetic structure having a hard axis that lies in the second direction, the third and fourth magnetic structures being spaced apart from each other and from the first and second magnetic structures, magnetic field lines from the first coil extending along the hard axes of the third and fourth magnetic structures; and

a second coil that touches the non-conductive member, the second coil being wrapped around the third magnetic structure.

16. The transformer of claim 15 wherein magnetic field lines within the first, second, third, and fourth magnetic structures extend substantially only along the hard axes of the first, second, third, and fourth magnetic structures.

17. A method of forming a transformer comprising:

forming a non-conductive structure;

forming a magnetic core structure including;

forming a first magnetic structure that touches the non-conductive structure, the first magnetic structure having a hard axis that lies in a first direction, and a bottom surface that lies in a horizontal plane;

forming a second magnetic structure that touches the non-conductive structure, the second magnetic structure having a hard axis that lies in a second direction different from the first direction, and a bottom surface; and

forming a third magnetic structure that touches the non-conductive structure, the third magnetic structure having a hard axis that lies in the first direction, and a bottom surface that lies in the horizontal plane, the first, second, and third magnetic structures being spaced apart from each other; and

forming a first coil that touches the non-conductive structure, the first coil being wrapped around the first magnetic structure so that magnetic field lines from the first coil extend along the hard axes of the first, second, and third magnetic structures.

18. The method of claim 17 wherein the bottom surface of the second magnetic structure lies above and spaced apart from the horizontal plane.

19. The method of claim 17 and further comprising forming a second coil that touches the non-conductive structure, the second coil being wrapped around only the third magnetic structure.

20. The method of claim 17 and further comprising forming a fourth magnetic structure that touches the non-conductive structure, the fourth magnetic structure having a hard axis that lies in the second direction, and a bottom surface that lies above and spaced apart from the horizontal plane, the fourth magnetic structure being spaced apart from the first, second, and third magnetic structures, magnetic field lines from the first coil within the first, second, third, and fourth magnetic structures extending along substantially only the hard axes of the first, second, third, and fourth magnetic structures.