Shielded three-terminal flat-through EMI/energy dissipating filter

• US 8,195,295 B2
• Filed: 03/19/2009
• Issued: 06/05/2012
• Est. Priority Date: 03/20/2008
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Stevenson, Robert A., Truex, Buehl E., Brendel, Richard L., Frysz, Christine A., Dabney, Warren S., Hussein, Haytham, Adame, Jose Luis Lorente, Johnson, Robert Shawn, Brainard, Scott
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): Bays, Pamela M
• Application Number:
  US12/407,402
• Publication Number:
  US 20090243756A1
• Time in Patent Office: 1,174 Days
• Field of Search: 607/36, 607/37, 607/45, 607/63, 607/115, 607/116, 607/119, 361/302
• US Class Current: 607/36
• CPC Class Codes: A61N 1/08 Arrangements or circuits for monitoring, protecting, controlling or indicating for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 4/06 Solid dielectrics
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors
• CPC Class Codes: H01G 4/40 Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01R 13/7195 with planar filters with openings for contacts
• CPC Class Codes: H03H 1/0007 of radio frequency interference filters
• CPC Class Codes: H03H 2001/0042 Wound, ring or feed-through type capacitor
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets
• CPC Class Codes: H03H 7/1766 Parallel LC in series path H03H7/1783 takes precedence
• CPC Class Codes: H05K 1/181 associated with surface mounted components
• CPC Class Codes: H05K 2201/10015 Non-printed capacitor
• CPC Class Codes: H05K 5/0095 hermetically-sealed
• CPC Class Codes: H05K 9/00 Screening of apparatus or components against electric or magnetic fields devices for absorbing radiation from an antenna H01Q17/00

Abstract

A shielded three-terminal flat-through EMI/energy dissipating filter includes an active electrode plate through which a circuit current passes between a first terminal and a second terminal, a first shield plate on a first side of the active electrode plate, and a second shield plate on a second side of the active electrode plate opposite the first shield plate. The first and second shield plates are conductively coupled to a grounded third terminal. In preferred embodiments, the active electrode plate and the shield plates are at least partially disposed with a hybrid flat-through substrate that may include a flex cable section, a rigid cable section, or both.

Claims

1. A shielded three-terminal flat-through EMI/energy dissipating filter, comprising:

an active electrode plate through which a circuit current passes between a first terminal and a second terminal;

a first shield plate on a first side of the active electrode plate; and

a second shield plate on a second side of the active electrode plate opposite the first shield plate;

wherein the first and second shield plates are conductively coupled to a grounded third terminal; and

wherein the surface area of the active electrode plate is maximized to increase parasitic capacitance to a minimum of 20 pf and minimize resistance to current flow.

2. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate is insulated from the shield plates by a dielectric material such that the active electrode plate and the shield plates cooperatively form a flat-through capacitor.

3. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 2, including a lead wire extending through at least one of the shield plates in non-conductive relation, the lead wire being conductively coupled to the active electrode plate to form the first terminal.

4. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 3, including a plurality of active electrode plates each having a first shield plate on a first side thereof and a second shield plate on a second side thereof opposite the first shield plate, wherein each active electrode plate is insulated from its adjacent shield plates by a dielectric material such that each active electrode plate and its adjacent shield plates cooperatively form a flat-through capacitor.

5. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 3, wherein the shield plates are conductively coupled to a common ground.

6. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 3, including a plurality of lead wires each extending through at least one of the shield plates in non-conductive relation, where each lead wire is conductively coupled to a respective active electrode plate to form the first terminal for said active electrode plate.

7. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 3, including a shielded fixture through which the lead wire extends in non-conductive relation.

8. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 7, wherein the fixture comprises an hermetic seal.

9. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 3, including an adjacent feedthrough capacitor through which the lead wire extends prior to conductively coupling to the active electrode plate to form the first terminal.

10. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 2, including at least one via hole for conductively coupling the shield plates to one another.

11. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 10, wherein the via holes are disposed about the periphery of the active electrode plate.

12. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 2, wherein the active electrode plate and the shield plates are at least partially disposed within a hybrid flat-through substrate.

13. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 12, wherein the hybrid flat-through substrate includes surface metallization forming the third terminal.

14. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 13, wherein the hybrid flat-through substrate is disposed adjacent to a hermetic seal for an implantable medical device such that the surface metallization is conductively coupled to a housing for the implantable medical device.

15. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 12, wherein the hybrid flat-through substrate comprises a flex cable section.

16. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 15, wherein the flex cable section comprises a polyimide, Kapton or acrylic material.

17. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 15, wherein the flex cable section comprises a plurality of flexible sections.

18. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 12, wherein the hybrid flat-through substrate comprises a rigid section.

19. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 18, wherein the rigid section comprises a high dielectric constant ceramic, alumina, fiberglass or FR4 material.

20. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 18, wherein the rigid section includes at least one passive electronic component conductively coupled to the active electrode plate.

21. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 20, wherein the passive electronic component comprises an RFID chip, a capacitor, an inductor, a band stop filter, an L-C trap filter, a diode, or a diode array.

22. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 21, wherein the capacitor comprises a monolithic chip capacitor.

23. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 21, wherein the inductor comprises a monolithic chip inductor or a toroidal inductor.

24. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 21, wherein the RFID chip includes a wake-up feature for initializing AIMD RF telemetry circuits.

25. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 18, wherein the second terminal of the active electrode plate is conductively coupled to a circuit board.

26. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a conductive pad conductively coupled to the active electrode plate and forming the second terminal.

27. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 26, wherein the conductive pad comprises a wire bond pad disposed on an exterior surface of a body of dielectric material through which the active electrode plate extends.

28. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a plurality of co-planar active electrode plates insulated from the shield plates by a dielectric material such that each active electrode plate and the shield plates cooperatively form a flat-through capacitor.

29. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 28, wherein at least one of the co-planar active electrode plates comprises an inductor.

30. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 28, including a co-planar third shield plate extending between the co-planar active electrode plates.

31. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a lead wire or pin extending through at least one of the shield plates in non-conductive relation, the lead wire or pin conductively coupling to the active electrode plate to form the second terminal.

32. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a monolithic chip capacitor (MLCC) conductively coupled between the active electrode plate and at least one of the grounded shield plates.

33. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a third shield plate disposed generally co-planarly with the active electrode plate, wherein the third shield plate is conductively coupled to the grounded third terminal.

34. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 33, wherein the third shield plate substantially surrounds the active electrode plate and is disposed between the first and second shield plates.

35. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein at least a portion of the active electrode plate comprises an inductor.

36. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 35, wherein the inductor comprises a spiral circuit trace.

37. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate is configured to form at least a component of an “

L”

, “

π

”

, “

T”

, “

LL”

, “

5 element”

, or an “

n”

element passive electronic low-pass filter.

38. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 37, wherein the active electrode plate is configured to form at least a component of a band stop filter, a diode array, or an RFID chip.

39. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 37, wherein the passive electronic device is optimized for use at MRI frequencies.

40. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate and the first and second shield plates are disposed generally perpendicular to a lead wire conductively coupled to the active electrode plate to form the first terminal.

41. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate and the first and second shield plates are disposed generally parallel to a lead wire conductively coupled to the active electrode plate to form the first terminal.

42. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein all external components thereof comprise biocompatible materials designed for direct body fluid exposure.

43. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the effective capacitance area of the active electrode plate and its surrounding grounded shielded plates has been relatively maximized in order to achieve a higher value of a three-terminal flat-through capacitor formed therebetween.

44. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 43, wherein the dielectric constant of insulating layers between the active electrode plate and the grounded shield plates has also been substantially raised in order to achieve a higher capacitance value of the three-terminal flat-through capacitor.

45. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 43, wherein a thickness of dielectric material separating the active electrode plate and the grounded shielded plates has been relatively minimized in order to achieve a higher capacitance value for the three-terminal flat-through capacitor.

46. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 43, including a number of redundant parallel layers of the active electrode plate and surrounding grounded shield plates in order to increase total capacitance value of the three-terminal flat-through capacitor.

47. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a feedthrough capacitor disposed adjacent to the flat-through capacitor and conductively coupled thereto.

48. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 47, including at least one lead wire extending through the feedthrough capacitor and into the flat-through capacitor to conductively couple active electrodes thereof.

49. A shielded three-terminal flat-through EMI/energy dissipating filter, comprising:

an active electrode plate through which a circuit current passes between a first terminal and a second terminal;

a first shield plate on a first side of the active electrode plate; and

a second shield plate on a second side of the active electrode plate opposite the first shield plate;

wherein the first and second shield plates are conductively coupled to a grounded third terminal;

wherein the active electrode plate is insulated from the shield plates by a dielectric material such that the active electrode plate and the shield plates cooperatively form a flat-through capacitor;

wherein the active electrode plate and the shield plates are at least partially disposed within a hybrid flat-through substrate; and

wherein the hybrid flat-through substrate comprises a dielectric material with the active electrode plate imbedded therein, the active electrode plate being conductively coupled to surface metallization for at least one via hole through the substrate, and wherein the shield plates comprise surface metallization applied to exterior surfaces of the hybrid flat-through substrate.

50. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 49, including a conductive cap configured to capture the hybrid flat-through substrate and conductively couple the shield plates to a ground.

51. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 50, including a hermetic seal for an implantable medical device, the hermetic seal including a conductive ferule to which the conductive cap is conductively attached, at least one lead wire extending through the ferule in non-conductive relation and conductively coupled to the surface metallization of the via hole.

52. A shielded three-terminal flat-through EMI/energy dissipating filter, comprising:

an active electrode plate through which a circuit current passes between a first terminal and a second terminal;

a first shield plate on a first side of the active electrode plate; and

a second shield plate on a second side of the active electrode plate opposite the first shield plate;

wherein the first and second shield plates are conductively coupled to a grounded third terminal;

wherein shielded three-terminal flat-through EMI/energy dissipating filter is incorporated into a passive component network for an implantable lead of an active implantable medical device (AIMD), comprising;

at least one lead wire having a length extending between and to a proximal end and a tissue-stimulating or biological-sensing electrode at a distal end;

an energy dissipative surface disposed adjacent to tissue or within the blood or lymph flow of a patient at a point distant from the electrode; and

a diversion circuit associated with the lead wire, for selectively diverting high-frequency energy away from the electrode to said energy dissipative surface for dissipation of said high-frequency energy as heat.

53. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein the passive component network includes an impeding circuit associated with the diversion circuit, for raising the high-frequency impedance of the lead wire, said impeding circuit being disposed between said diversion circuit and the distal end of said at least one lead wire.

54. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 53, wherein the impeding circuit comprises an inductor or a bandstop filter.

55. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 53, wherein the impeding circuit includes a nonlinear circuit element.

56. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 55, wherein the nonlinear circuit element comprises a diode or a transient voltage suppressor.

57. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 56, wherein the diversion circuit comprises at least one series resonant L-C trap filter.

58. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 56, wherein the impeding circuit comprises an inductor or a bandstop filter.

59. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein the at least one lead wire comprises a portion of a probe or a catheter.

60. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein the energy dissipative surface comprises a sheath, an insulative body, or a thermally conductive element.

61. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 60, wherein the energy dissipating surface comprises a housing for the AIMD.

62. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein said at least one lead wire comprises at least a pair of lead wires each having a length extending between and to a proximal end and a tissue-stimulating or biological-sensing electrode at a distal end.

63. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 62, wherein said diversion circuit couples each of said lead wires to said energy dissipative surface.

64. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 63, wherein said diversion circuit is coupled between said pair of lead wires.

65. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein the high-frequency energy comprises an RF pulsed frequency of a magnetic resonance scanner.

66. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 65, wherein the high-frequency energy comprises a range of selected RF pulsed frequencies.

67. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein the diversion circuit comprises a low pass filter.

68. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 67, wherein the low pass filter comprises at least one of a C filter, an L filter, a T filter, a Pi filter, an LL filter, a 5-element filter, or an “

n”

element filter.

69. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 52, wherein the diversion circuit comprises at least one series resonant L-C trap filter.