Inductive devices having conductive areas on their surfaces

• US 6,246,311 B1
• Filed: 11/26/1997
• Issued: 06/12/2001
• Est. Priority Date: 11/26/1997
• Status: Expired due to Term

• Current Assignee: VLT Incorporated (Vicor Corporation)
• Original Assignee: VLT Incorporated (Vicor Corporation)
• Inventors: Montminy, Steven N., Vinciarelli, Patrizio, Finnemore, Fred M.
• Primary Examiner(s): Mai, Anh
• Application Number:
  US08/979,518
• Time in Patent Office: 1,294 Days
• Field of Search: 336/192, 336/83, 336/229, 336/65
• US Class Current: 336/192
• CPC Class Codes: H01F 17/062 Toroidal core with turns of coil around it
• CPC Class Codes: H01F 27/292 Surface mounted devices

Abstract

An inductive device includes a magnetic core, a conductive winding surrounding the core, a conductive element formed on a selected portion of the surface of the magnetic core, and a termination of the winding mechanically attached and electrically connected to the conductive element.

In an assembly that includes a circuit board the conductive element is mechanically attached and electrically connected to a connection pad on the board and the winding termination is connected to the conductive element.

Claims

1. An inductive device comprising

a magnetic core comprising a loop of magnetic material defining a flux path surrounding an aperture, the aperture extending completely between external surfaces of the core,

first and second electrically conductive elements formed on selected portions of the external surfaces of the core along the loop;

a first conductive winding having one or more turns of a conductor wound over the external surfaces on which the conductive elements are formed and primarily located between the conductive elements, the winding enclosing the flux path, each of the turns being threaded through the aperture, and

first and second terminations of the first winding mechanically attached and electrically connected to the first and second conductive elements.

2. The inductive device of claim 1 wherein the loop comprises an inside perimeter and an outside perimeter, and wherein at least one of the inside and outside perimeters is non-circular.

3. The inductive device of claim 2 wherein the inside and outside perimeters are non-circular.

4. The inductive device of claim 3 wherein the inside perimeter comprises a square and the outside perimeter comprises an octagon.

5. The inductive device of claim 4 wherein the core comprises flat top and bottom surfaces.

6. The inductive device of claim 4 wherein

at least one of the conductive elements forms a shield for controlling leakage flux emanation from the core, and

the shield covers substantially all of the corners and edges of the outer perimeter of the core.

7. The device of claim 1, 2, 3, 4, or 5 further comprising

a second conductive winding having turns enclosing the flux path, the second winding comprising two terminations,

two additional electrically isolated conductive elements formed on selected portions of the external surface of the core, mechanically attached and electrically connected to the two terminations of the second winding.

8. The inductive device of claim 7 wherein at least one of the conductive elements forms a shield for controlling leakage flux emanation from the core.

9. The inductive device of claim 8 wherein each of the conductive elements forms a shield for controlling leakage flux emanation from the core.

10. The inductive device of claim 8 wherein the first and second conductive windings are separated by a distance along the flux path and the conductive elements are located between the windings.

11. The inductive device of claim 8 wherein edges formed in the outer circumference of the loop are covered by the shield.

12. The inductive device of claim 1 wherein

at least one of said first and second conductive elements is arranged to form a shield for controlling leakage flux emanating from the core.

13. The inductive device of claim 12 wherein the shield covers portions of the outer circumference of the core.

14. The inductive device of claim 12 wherein the shield covers substantially all of the outer circumference of the core.

15. The inductive device of claim 12 wherein the shield covers substantially all of the outer circumference and the bottom of the core.

16. The inductive device of claim 12 wherein the shield covers substantially all of the outer circumference, the top, and the bottom of the core.

17. The inductive device of claim 12, 13, 14, 15, or 16 wherein the magnetic core comprises an electrical insulation layer.

18. The inductive device of claim 17 wherein the insulation layer comprises a para-xylylene polymer.

19. The inductive device of claim 17 further comprising:

a second conductive winding having turns enclosing the flux path, the winding comprising two terminations,

two additional electrically isolated conductive elements formed on selected portions of the external surface of the magnetic core and arranged to form shields for controlling leakage flux emanating from the core, wherein the two additional conductive elements are mechanically attached and electrically connected to the two terminations of the second winding.

20. The inductive device of claim 17 wherein the loop comprises an inside perimeter and an outside perimeter, and wherein at least one of the inside or outside perimeters is non-circular.

21. The inductive device of claim 20 wherein the inside and outside perimeters are non-circular.

22. The inductive device of claim 21 wherein the inside perimeter comprises a square and the outside perimeter comprises an octagon.

23. The inductive device of claim 16 wherein the core comprises flat top and bottom surfaces.

24. The inductive device of claim 23 wherein the shields cover all of the corners of the octagon and portions of the corners formed by the junction of the outside perimeter along the top and bottom of the core.

25. The device of claim 24 further comprising

a second conductive winding having turns enclosing the flux path , the winding comprising two terminations,

two additional electrically isolated conductive elements formed on selected portions of the external surface of the magnetic core and arranged to form shields for controlling leakage flux emanating from the core, wherein the two additional conductive elements are mechanically attached and electrically connected to the two terminations of the second winding.

26. An assembly comprising the device of claim 25 and further comprising

a circuit board bearing connection pads, and

the conductive elements each being mechanically attached and electrically connected to a respective connection pad.

27. The inductive device of claim 26 wherein the terminations of the windings and the connection pads are mechanically attached to the conductive elements on the bottom of the core.

28. The device of claim 12, 13, 14, 15, or 16 further comprising

a second conductive winding having turns enclosing the flux path, the winding comprising two terminations,

two additional electrically isolated conductive elements formed on selected portions of the external surface of the magnetic core and arranged to form shields for controlling leakage flux emanating from the core, wherein the two additional conductive elements are mechanically attached and electrically connected to the two terminations of the second winding.

29. An assembly comprising the inductive device of claim 1, 2, 3, 4, 5, 12, 13, 14, 15, or 16 and further comprising

a circuit board bearing connection pads, and

the conductive elements each being mechanically attached and electrically connected to a respective connection pad.

30. The assembly of claim 29 wherein the terminations of the windings and the connection pads are mechanically attached to the conductive elements at the bottom of the core.

31. The inductive device of claim 12, 13, 14, 15, or 16 wherein the loop comprises an inside perimeter and an outside perimeter, and wherein at feast one of the inside or outside perimeters is non-circular.

32. The inductive device of claim 31 wherein the inside and outside perimeters are non-circular.

33. The inductive device of claim 32 wherein the inside perimeter comprises a square and the outside perimeter comprises an octagon.

34. The inductive device of claim 33 wherein the magnetic core comprises flat top and bottom surfaces.

35. The inductive device of claim 31 wherein the loop is annular.

36. The inductive device of claim 31 wherein the loop is a toroid.

37. The inductive device of claim 1 or 12 wherein the winding comprises metallic wire.

38. The inductive device of claim 1 or 12 wherein the winding further comprises an insulation layer.

39. The inductive device of claim 1 or 12 wherein the winding comprises metallic foil.

40. The inductive device of claim 1 or 12 wherein the winding comprises metallic film lines.

41. The inductive device of claim 1 or 12 wherein the conductive element comprises a silver-filled epoxy.

42. The inductive device of claim 1 or 12 wherein the conductive element comprises copper.

43. The inductive device of claim 1 or 12 wherein the conductive element comprises tin.

44. The inductive device of claim 1 or 12 wherein the conductive element comprises layers.

45. The inductive device of claim 1 or 12 wherein the magnetic core comprises ferrite material.

46. The inductive device of claim 1 or 12 wherein the magnetic core comprises iron powder material.

47. The inductive device of claim 1 or 12 wherein the core comprises flat top and bottom surfaces.

48. The inductive device of claim 1 wherein

the loop comprises an outside perimeter,

at least one of the conductive elements forms a shield for controlling leakage flux emanation from the core, and

the shield covers substantially all of the corners and edges of the outer perimeter of the core.