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

• US 7,957,806 B2
• Filed: 09/27/2010
• Issued: 06/07/2011
• Est. Priority Date: 03/20/2008
• Status: Expired due to Fees

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Frysz, Christine A., Dabney, Warren S., Brendel, Richard L., Stevenson, Robert A., Brainard, Scott, Truex, Buehl E., Johnson, Robert Shawn, Lorente-Adame, Jose Luis, Hussein, Haythem, Williams, Christopher Michael
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Bays; Pamela M
• Application Number:
  US12/891,542
• Publication Number:
  US 20110004283A1
• Time in Patent Office: 253 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 inside PCB filters H05K
• 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. An EMI/energy dissipating filter for an active implantable medical device (AIMD), comprising:

an electromagnetically shielded conductive housing for the AIMD;

a hermetic terminal assembly for passage of at least one conductor through the AIMD housing in non-conductive relation therewith;

at least one AIMD electronic circuit disposed within the AIMD housing; and

a shielded three-terminal flat-through EMI/energy dissipating filter conductively coupled between the conductor and the AIMD electronic circuit, 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; and

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

2. The EMI/energy dissipating filter of claim 1, wherein the shielded three-terminal flat-through EMI/energy dissipating filter is mounted directly onto at least a portion of the hermetic terminal.

3. The EMI/energy dissipating filter of claim 1, wherein the grounded third terminal is conductively coupled to the conductive housing for the AIMD.

4. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, including a lead wire extending to or 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.

5. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 4, 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.

6. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 4, wherein the shield plates are conductively coupled to a common ground.

7. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 4, 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.

8. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 4, including a shielded fixture through which the lead wire extends in non-conductive relation.

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

10. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 4, including a feedthrough capacitor conductively coupled to the active electrode plate to form the first terminal.

11. 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, 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.

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

13. 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.

14. 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.

15. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 14, wherein the passive electronic device is optimized for use at MRI frequencies.

16. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate and the shield plates are at least partially disposed within a hybrid flat-through substrate comprising a rigid section having at least one passive electronic component conductively coupled to the active electrode plate, wherein the passive electronic component comprises an RFID chip, a capacitor, an inductor, a bandstop filter, an L-C trap filter, a diode, or a diode array.

17. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate is a component of an L-C trap filter.

18. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate is a component of a bandstop filter.

19. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate is a component of an L-C trap filter, a bandstop filter and a feedthrough capacitor conductively coupled to one another.

20. The shielded three-terminal flat-through EMI/energy dissipating filter of claim 1, wherein the active electrode plate is conductively connected to a passive or active electronic component mounted on a surface of, or embedded within, a substrate.