Using the Case of an Implantable Medical Device to Broaden Communication Bandwidth

• US 20110112612A1
• Filed: 03/03/2010
• Published: 05/12/2011
• Est. Priority Date: 11/11/2009
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Rahman, Md. Mizanur
• Granted Patent: US 8,457,756 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3758 Packaging of the components within the casing
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/44 using equipment having another main function to serve additionally as an antenna , e.g. means for giving an antenna an aesthetic aspectH01Q1/27 - H01Q1/34 take precedence
• CPC Class Codes: Y10T 29/49018 with other electrical component

Abstract

An improved implantable pulse generator (IPG) containing improved telemetry circuitry is disclosed. The IPG includes a telemetry coil within the conductive IPG case, not in the non-conductive header as is typical, which simplifies IPG design. The improved resonant circuit of which the coil is a part does not include a discrete tuning resistor with the coil, which tuning resistor was traditionally used to increase communication bandwidth of the coil to render it suitable for FSK telemetry. In lieu of the tuning resistor, the coil is intentionally inductively coupled to the case by positioning the coil a certain distance away from the case. Such coupling decreases the effective inductance and increases the effective series resistance in the improved resonant circuit, both of which increase the communication bandwidth. As such, suitable FSK telemetry can be achieved, even though the improved resonant circuit without the case would not on its own have suitable bandwidth.

Claims

1. An implantable medical device, comprising:

a conductive case;

a resonant circuit within the case for transmitting, receiving, or transmitting and receiving data at least two frequencies each representing a digital logic state, each the resonant circuit comprising;

a telemetry coil; and

a capacitor,

wherein the resonant circuit does not include a discrete resistor.

2. The device of claim 1, wherein the telemetry coil and the capacitor are coupled in series.

3. The device of claim 1, wherein the telemetry coil and the capacitor are coupled in parallel.

4. The device of claim 1, further comprising a non-conductive header coupled to the conductive case.

5. The device of claim 1, further comprising at least one lead connector within the non-conductive header for coupling to an electrode lead.

6. The device of claim 1, wherein the conductive case is planar, and wherein the telemetry coil is wound in a plane parallel to a plane of the case, and separated from the plane of the case by a distance.

7. The device of claim 1, wherein coupling between the case and the coil at least doubles a bandwidth of the resonant circuit.

8. An implantable medical device, comprising:

a planar conductive case;

a resonant circuit within the case for transmitting, receiving, or transmitting and receiving data at least two frequencies each representing a digital logic state, each the resonant circuit comprising;

a telemetry coil, wherein the telemetry coil is wound in a plane parallel to a plane of the case, and spaced from the plane of the case by a distance; and

a capacitor.

9. The device of claim 8, wherein the resonant circuit does not include a discrete resistor.

10. The device of claim 8, further comprising a non-conductive header coupled to the conductive case.

11. The device of claim 8, further comprising at least one lead connector within the non-conductive header for coupling to an electrode lead.

12. The device of claim 8, wherein the telemetry coil is separated from the plane of the case by a distance.

13. The device of claim 8, wherein coupling between the case and the coil at least doubles a bandwidth of the resonant circuit.

14. An implantable medical device, comprising:

a resonant circuit which in isolation has a first bandwidth, the resonant circuit comprising a telemetry coil and a capacitor, wherein the first bandwidth is too narrow to transmit, receive, or transmit and receive data at least two frequencies each representing a digital logic state; and

a conductive case, wherein the resonant circuit is positioned within the conductive case, wherein the resonant circuit inside the conductive case has a second bandwidth larger than the first bandwidth, wherein the second bandwidth is broad enough to transmit, receive, or transmit and receive data at the at least two frequencies each representing a digital logic state.

15. The device of claim 14, wherein the resonant circuit does not include a discrete resistor.

16. The device of claim 14, further comprising a non-conductive header coupled to the conductive case.

17. The device of claim 14, further comprising at least one lead connector within the non-conductive header for coupling to an electrode lead.

18. The device of claim 14, wherein the conductive case is planar, and wherein the telemetry coil is wound in a plane parallel to a plane of the case, and separated from the plane of the case by a distance.

19. The device of claim 18, wherein coupling between the case and the coil at least doubles a bandwidth of the resonant circuit.

20. The device of claim 14, wherein the first bandwidth is determined by an inductance of the coil and a self resistance of the coil.

21. The device of claim 20, wherein the second bandwidth is determined by the effect of coupling between the coil and the case.