Narrowbody coil isolator

• US 8,093,983 B2
• Filed: 03/31/2010
• Issued: 01/10/2012
• Est. Priority Date: 08/28/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Fouquet, Julie, Ho, Dominique
• Primary Examiner(s): Pert, Evan
• Application Number:
  US12/751,971
• Publication Number:
  US 20100188182A1
• Time in Patent Office: 650 Days
• Field of Search: 336/200, 336/232, 257/531, 257/676, 257/692, 257/725, 257/E23.011, 257/E23.043, 257/E23.052, 257/E23.079, 438/123
• US Class Current: 336/200
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H01F 17/0013 with stacked layers
• CPC Class Codes: H01F 19/08 Transformers having magnetic bias, e.g. for handling pulses
• CPC Class Codes: H01F 2019/085 Transformer for galvanic isolation
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 27/40 Structural association with built-in electric component, e.g. fuse
• 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: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H03H 7/46 Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source for use in multiplex transmission systems H04J1/00
• CPC Class Codes: H03H 7/52 One-way transmission networks, i.e. unilines
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/75 for isolation purposes
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

Disclosed herein are various embodiments of narrowbody coil isolators containing multiple coil transducers, where integrated circuits are not stacked vertically over the coil transducers. The disclosed coil isolators provide high voltage isolation and high voltage breakdown performance characteristics in small packages that provide a high degree of functionality at a low price.

Claims

1. A coil isolator, comprising:

a coil transducer having opposing first and second ends and comprising a dielectric barrier having opposing first and second sides, the dielectric barrier comprising an electrically insulating, non-metallic, non-semiconductor, low-dielectric-loss material, a first electrically conductive transmitter coil disposed near or on the first side, first leads extending between the first coil and wire bond pads corresponding thereto, and a second electrically conductive receiver coil disposed near or on the second side, second leads extending between the second coil and wire bond pads corresponding thereto, the dielectric barrier being disposed between the first and second coils, and

at least first and second lead frames;

wherein the coil transducer extends horizontally between the first and second lead frames and the first and second ends extend onto or beneath at least portions of the first and second lead frames, no portions of the first and second lead frames are disposed vertically over or beneath any portions of the first and second coils, and the wire bond pads of the first and second coils are disposed vertically over or beneath the first and second lead frames, respectively.

2. The coil isolator of claim 1, wherein the coil transducer is a flex circuit.

3. The coil isolator of claim 1, further comprising a transmitter circuit comprising transmitter output terminals, the transmitter output terminals being operably connected to the first coil through the wire bond pads corresponding thereto.

4. The coil isolator of claim 3, wherein the transmitter circuit is configured to provide differential output signals across the first coil.

5. The coil isolator of claim 1, further comprising a receiver circuit comprising receiver input terminals, the receiver input terminals being operably connected to the second coil through the wire bond pads corresponding thereto.

6. The coil isolator of claim 5, wherein the receiver circuit is configured to receive differential input signals.

7. The coil isolator of claim 6, wherein the receiver circuit is an integrated circuit.

8. The coil isolator of claim 1, wherein the first and second coils are spatially arranged and configured respecting one another such that at least one of power and data signals may be transmitted by the first coil to the second coil across the dielectric barrier.

9. The coil isolator of claim 1, wherein the first and second coils have, in combination, at least five turns, at least eight turns, at least ten turns, or at least twenty turns.

10. The coil isolator of claim 1, wherein the dielectric barrier comprises fiberglass, glass, ceramic, polyimide, polyimide film, a polymer, an organic material, a flex circuit material, epoxy, epoxy resin, a printed circuit board material, PTFE and glass, PTFE and ceramic, glass and ceramic, thermoset plastic, or plastic.

11. The coil isolator of claim 1, wherein a breakdown voltage between the first coil and the second coil exceeds about 2,000 volts RMS when applied over a time period of about one minute, exceeds about 2,000 volts RMS when applied over a time period of about six minutes, exceeds about 2,000 volts RMS when applied over a time period of 24 hours, exceeds about 5,000 volts RMS when applied over a time period of about one minute, exceeds about 5,000 volts RMS when applied over a time period of about six minutes, or exceeds about 5,000 volts RMS when applied over a time period of 24 hours.

12. The coil isolator of claim 1, wherein the coil transducer further comprises internal voltage supply routing.

13. The coil isolator of claim 1, wherein the coil transducer further comprises ground routing or one or more ground pads.

14. The coil isolator of claim 1, wherein the first and second coils comprise a metal, a metal alloy or a metal combination.

15. The coil isolator of claim 1, wherein the coil transducer and at least portions of the first and second lead frames are encapsulated with a molding material comprising silica-loaded epoxy.

16. The coil isolator of claim 1, wherein a length of the coil transducer between the first and second ends is less than about 2.5 mm.

17. The coil isolator of claim 1, wherein a width of the coil transducer is less than about 1.5 mm.

18. The coil isolator of claim 1, wherein all wire bond pads for coils of the coil transducer are located to one side of a major axis of the coil transducer.

19. The coil isolator of claim 1, wherein wire bond pads for coils of the coil transducer are located on both sides of a major axis of the coil transducer.

20. The coil isolator of claim 1, further comprising a package comprising the coil transducer, the first and second lead frames, and transmitter and receiver circuits, the package having a length less than about 20 mm or less than about 12 mm.

21. The coil isolator of claim 1, further comprising a package comprising the coil transducer, the first and second lead frames, and transmitter and receiver circuits, the package having a width less than about 10 mm, less than about 6 mm, or less than about 4 mm.

22. The coil isolator of claim 1, further comprising a package wherein a transmitter and a receiver are not stacked vertically over any portions of the coil transducer.

23. The coil isolator of claim 1, further comprising a spacer layer disposed over the first or second sides of the coil transducer, the spacer layer comprising a low-dielectric-loss material.

24. The coil isolator of claim 23, wherein the spacer layer is configured to minimize the electrical interaction between at least some electrically conductive portions of the coil transducer and nearby electrical conductors or traces located outside the coil transducer.

25. The coil isolator of claim 23, wherein the spacer layer has a thickness ranging between about 25 microns and about 50 microns.

26. A method of making a coil isolator, comprising:

forming a coil transducer having opposing first and second ends and comprising a dielectric barrier having opposing first and second sides, the dielectric barrier comprising an electrically insulating, non-metallic, non-semiconductor, low-dielectric-loss material, a first electrically conductive transmitter coil disposed near or on the first side, first leads extending between the first coil and wire bond pads corresponding thereto, and a second electrically conductive receiver coil disposed near or on the second side, second leads extending between the second coil and wire bond pads corresponding thereto, the dielectric barrier being disposed between the first and second coils;

providing at least first and second lead frames, and

attaching the coil transducer to the first and second lead frames such that the coil transducer extends horizontally between the first and second lead frames and the first and second ends extend onto or beneath at least portions of the first and second lead frames, no portions of the first and second lead frames are disposed vertically over or beneath any portions of the first and second coils, and the wire bond pads of the first and second coils are disposed vertically over or beneath the first and second lead frames, respectively.

27. The method of claim 26, further comprising operably connecting a transmitter circuit having output terminals to the wire bond pads corresponding to the first coil.

28. The method of claim 26, further comprising operably connecting a receiver circuit having input terminals to the wire bond pads corresponding to the second coil.

29. The method of claim 26, wherein forming the coil transducer further comprises forming at least five turns, at least eight turns, at least ten turns, or at least twenty turns, in combination, in the first and second coils.

30. The method of claim 26, wherein forming the coil transducer further comprises employing fiberglass, glass, ceramic, polyimide, polyimide film, a polymer, an organic material, a flex circuit material, epoxy, epoxy resin, a printed circuit board material, PTFE and glass, PTFE and ceramic, glass and ceramic, thermoset plastic, or plastic to form the dielectric barrier.

31. The method of claim 26, wherein forming the coil transducer further comprises forming internal voltage supply routing therein or thereon.

32. The method of claim 26, wherein forming the coil transducer further comprises forming ground routing or one or more ground pads therein or thereon.

33. The method of claim 26, further comprising encapsulating the coil transducer and at least portions of the first and second lead frames with a molding material comprising silica-loaded epoxy.

34. The method of claim 26, wherein forming the coil transducer further comprises configuring the coil transducer to have a length between the first and second ends of less than about 2.5 mm.

35. The method of claim 26, wherein forming the coil transducer further comprises configuring the coil transducer to have a width less than about 1.5 mm.

36. The method of claim 26, wherein forming the coil transducer further comprises placing all wire bond pads for coils of the coil transducer to one side of a major axis of the coil transducer.

37. The method of claim 26, wherein forming the coil transducer further comprises placing wire bond pads for coils of the coil transducer on both sides of a major axis of the coil transducer.

38. The method of claim 26, further comprising forming a package comprising the coil transducer, the first and second lead frames, and transmitter and receiver circuits, where the package has a length less than about 20 mm or less than about 12 mm.

39. The method of claim 26, further comprising forming a package comprising the coil transducer, the first and second lead frames, and transmitter and receiver circuits, where the package has a width less than about 10 mm or less than about 4 mm.

40. The method of claim 26, further comprising forming a package wherein a transmitter and a receiver are not stacked vertically over any portions of the coil transducer.

41. The method of claim 26, further comprising placing a spacer layer over the first or second sides of the coil transducer, the spacer layer comprising a low-dielectric-loss material.