Ferrite core telemetry coil for implantable medical device

• US 7,103,413 B2
• Filed: 07/12/2002
• Issued: 09/05/2006
• Est. Priority Date: 07/12/2002
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Swanson, Lawrence, Von Arx, Jeffrey A., Taylor, Jeff, Balczewski, Ron, Carpenter, Greg
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US10/194,401
• Publication Number:
  US 20040010296A1
• Time in Patent Office: 1,516 Days
• Field of Search: 607 30- 33, 607/60, 607/5, 607/9, 604/891.1, 128/903
• US Class Current: 607/32
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

An implantable medical device such as a cardiac pacemaker with a telemetry coil located in the device header rather than the conductive housing. The telemetry coil has a core made of magnetically permeable material such as ferrite in order to increase the efficiency of the coil and lessen space requirements.

Claims

1. An implantable medical device, comprising:

a metal housing for containing electronic circuitry;

a non-conductive header for receiving external lead wires that are electrically connected to the electronic circuitry within the housing;

telemetry circuitry for communicating with an external programmer;

a telemetry coil assembly located in the header and connected to the telemetry circuitry, wherein the coil assembly includes coil windings wrapped around a core made of ferrite, and wherein the core is encapsulated so as to be biocompatible; and

,

wherein the coil assembly is encapsulated with polyurethane and includes a bobbin having biocompatible end caps for supporting the assembly within a molding vessel.

2. The device of claim 1 wherein the core is encapsulated with polyurethane.

3. The device of claim 1 wherein the core is coated with paralyne and then encapsulated in polyurethane.

4. The device of claim 1 wherein the coil assembly is encapsulated in glass and then encapsulated in polyurethane.

5. The device of claim 4 wherein the polyurethane is tecothane.

6. The device of claim 1 wherein the telemetry coil windings are constructed of wire with a silver core and a stainless steel sheath.

7. The device of claim 1 wherein the telemetry coil windings are constructed of wire with a tantulum core and a stainless steel sheath.

8. A method for constructing an implantable medical device, comprising:

disposing telemetry circuitry in a metal housing;

assembling a telemetry coil by wrapping coil windings around a ferrite core;

encapsulating the core in a manner that renders the core biocompatible;

encapsulating the coil assembly with polyurethane;

wrapping the coil windings around a bobbin having biocompatible end caps for supporting the assembly within a molding vessel; and

,

disposing the telemetry coil in a non-conductive header and electrically connecting the telemetry coil to the telemetry circuitry within the metal housing.

9. The method of claim 8 further comprising encapsulating the core with polyurethane.

10. The method of claim 8 further comprising coating the core with paralyne and then encapsulating the core in polyurethane.

11. The method of claim 8 further comprising encapsulating the coil assembly in glass and then in polyurethane.

12. The method of claim 11 wherein the polyurethane is tecothane.

13. The method of claim 8 wherein the telemetry coil windings are constructed of wire with a silver core and a stainless steel sheath.

14. The method of claim 8 wherein the telemetry coil windings are constructed of wire with a tantulum core and a stainless steel sheath.