Minimizing Interference Between Charging and Telemetry Coils in an Implantable Medical Device

• US 20140058479A1
• Filed: 10/03/2013
• Published: 02/27/2014
• 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, Nimmagadda, Kiran, Parramon, Jordi, Feldman, Emanuel
• Granted Patent: US 9,042,997 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• 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: A61N 1/3787 from an external energy source

Abstract

An improved implantable pulse generator (IPG) containing improved telemetry circuitry is disclosed. The IPG includes charging and telemetry coils within the IPG case, which increases their mutual inductance and potential to interfere with each other; particularly problematic is interference to the telemetry coil caused by the charging coil. To combat this, improved telemetry circuitry includes decoupling circuitry for decoupling the charging coil during periods of telemetry between the IPG and an external controller. Such decoupling circuitry can comprise use of pre-existing LSK circuitry during telemetry, or new discrete circuitry dedicated to decoupling. The decoupling circuitry is designed to prevent or at least reduce induced current flowing through the charging coil during data telemetry. The decoupling circuitry can be controlled by the microcontroller in the IPG, or can automatically decouple the charging coil at appropriate times to mitigate an induced current without instruction from the microcontroller.

Claims

1. An implantable medical device, comprising:

a case;

a charging coil within the case configured to wirelessly receive power, wherein the charging coil is wound in a first plane around a first area; and

a telemetry coil within the case configured to wirelessly receive data, or wirelessly transmit data, or wirelessly receive and transmit data, wherein the telemetry coil is wound in a second plane around a second area,

wherein the first and second planes are parallel, and wherein the second area of the telemetry coil at least overlaps the first area of the charging coil.

2. The device of claim 1, further comprising a circuit board, wherein the charging coil is proximate to one side of the circuit board, and the telemetry coil is proximate to the other side of the circuit board.

3. The device of claim 1, wherein the second area of the telemetry coil is entirely within the first area of the charging coil.

4. The device of claim 1, wherein the second area is smaller than the first area.

5. The device of claim 1, wherein the case is conductive.

6. The device of claim 1, further comprising a header comprising at least one lead connector configured to couple to an electrode lead.

7. The device of claim 6, wherein the header is non-conductive.

8. The device of claim 1, wherein the telemetry coil is not wound around a ferrite core.

9. The device of claim 1, further comprising decoupling circuitry controllable to reduce or remove a current in the charging coil when the telemetry coil is receiving or transmitting data.

10. The device of claim 1, further comprising decoupling circuitry controllable to reduce or remove a current in the charging coil when the telemetry coil is enabled to receive or transmit data.

11. The device of claim 1, wherein the first and second planes are parallel to first and second sides of the case.

12. The device of claim 1, further comprising a battery, and charging circuitry coupled between the battery and the charging coil, wherein the charging circuitry uses the received power to charge the battery.

13. The device of claim 12, wherein the battery is inside the charging coil.

14. The device of claim 1, wherein the charging coil is tuned to a first frequency matching the received power, and wherein the telemetry coil is tuned to a second frequency matching the data.