Ferrite core telemetry coil for implantable medical device

• US 20040010296A1
• Filed: 07/12/2002
• Published: 01/15/2004
• 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: Von Arx, Jeffrey A., Taylor, Jeff, Balczewski, Ron, Swanson, Lawrence, Carpenter, Greg
• Granted Patent: US 7,103,413 B2
• Time in Patent Office: Days
• US Class Current: 607/36
• 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; and

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 magnetically permeable material.

2. The device of claim 1 wherein the magnetically permeable material is ferrite.

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

4. The device of claim 2 wherein the core is coated with paralyne and then encapsulated in polyurethane.

5. The device of claim 2 wherein the coil assembly is encapsulated with polyurethane.

6. The device of claim 5 wherein the coil assembly includes a bobbin having biocompatible end caps for supporting the assembly within a molding vessel.

7. The device of claim 2 wherein the coil assembly is encapsulated in glass and then encapsulated in polyurethane.

8. The device of claim 7 wherein the polyurethane is tecothane.

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

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

11. 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 magnetically permeable core; and

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

12. The method of claim 11 wherein the magnetically permeable core is made of is ferrite.

13. The method of claim 12 further comprising encapsulating the core with polyurethane.

14. The method of claim 12 further comprising coating the core with paralyne and then encapsulating the core in polyurethane.

15. The method of claim 12 further comprising encapsulating the coil assembly with polyurethane.

16. The method of claim 15 further comprising wrapping the coil windings around a bobbin having biocompatible end caps for supporting the assembly within a molding vessel.

17. The method of claim 12 further comprising encapsulating the coil assembly in glass and then in polyurethane.

18. The method of claim 17 wherein the polyurethane is tecothane.

19. The method of claim 11 wherein the telemetry coil windings are constructed of wire with a silver core and a stainless steel sheath.

20. The method of claim 11 wherein the telemetry coil windings are constructed of wire with a tantulum core and a stainless steel sheath.