RF-energy modulation system through dynamic coil detuning

• US 7,209,792 B1
• Filed: 04/26/2002
• Issued: 04/24/2007
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: Marnfeldt, Goran N., Parramon, Jordi
• Primary Examiner(s): Pezzuto; Robert E.
• Assistant Examiner(s): Oropeza; Frances P.
• Application Number:
  US10/133,766
• Time in Patent Office: 1,824 Days
• Field of Search: 607/2, 607/4, 607/5, 607/9, 607/10, 607 30- 33, 607 60- 62, 607/48, 607/49, 323/222, 343/860, 343/861, 333/17.3, 333/32
• US Class Current: 607/120
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

An RF-energy modulation system dynamically adjusts tuned receiving circuits within a plurality of slave devices, thereby regulating the level of power reception in each slave device. The slave devices receive power from a single master device, through coupling of a primary antenna in the master device with a secondary antenna in each slave device. The amount of the power received by each slave device is a function of the antenna separation distance, and is thus different at each slave device location. The RF-energy modulation system monitors the power requirements of the slave device within which the modulation system is included, and modulates the tuning of the secondary antenna to maintain the proper power reception level. Advantageously, such modulation controls the power reception by the slave device, versus dissipating energy already received by the slave device. In a preferred embodiment, the RF-energy modulation system controls the power received by a multiplicity of microstimulators implanted in a single patient.

Claims

1. A power reception circuit for regulating power received from a master device, comprising:

a secondary antenna for receiving power and outputting a current;

a matching network configured to electrically cooperate with the secondary antenna to tune the power reception circuit to efficiently receive power from the master device; and

a control circuit connected to said antenna and said matching network, wherein said control circuit comprises either a current or temperature monitor and selectively tunes and detunes said power reception circuit in response to the current output by the secondary antenna or a temperature.

2. The circuit of claim 1 wherein the power reception circuit resides in a slave device, and wherein the master device provides power to the slave device.

3. The circuit of claim 2 wherein the slave device includes an energy storage device, and wherein the power recharges the energy storage device.

4. The circuit of claim 3 wherein the energy storage device comprises a battery.

5. The system of claim 1 wherein the master device includes a primary coil, and wherein the secondary antenna comprises a secondary coil, and wherein the power is inductively transmitted from the primary coil to the secondary coil.

6. The system of claim 1 wherein the master device is a master controller of an implantable medical device system, and wherein the power reception circuit resides in each of a plurality of implantable microdevices.

7. The system of claim 6 wherein the implantable microdevices comprise implantable microstimulators.

8. The system of claim 6 wherein the implantable microdevices comprise implantable microsensors.

9. The system of claim 6 wherein the implantable microdevices comprise implantable microsensors and implantable microstimulators.

10. A power reception circuit for regulating power received from a master device, comprising:

a secondary antenna;

a matching network connected with the secondary antenna and configured to selectively tune the power reception circuit to efficiently receive power from the master device; and

means for controlling the power reception circuit to retunably detune the power reception circuit;

wherein the means for controlling the power reception circuit comprise at least one of a current or temperature monitor and are configured to detune the power reception circuit when the current or temperature produced by the slave device exceeds a first threshold, and to retune the power reception circuit when the current or temperature produced by the slave device is less than a second threshold.

11. A power reception circuit for an implantable device, comprising:

an antenna;

a first node V1, wherein the antenna is electrically connected between the node V1 and a reference potential;

a tuning element connected between the node V1 and the reference potential;

a detuning means configured to selectively detune the power reception circuit; and

a control circuit comprising at least one of a current or temperature monitor, wherein said control circuit is configured to selectively control the detuning means in response to either a current or temperature produced by the implantable device so as to maintain power received by the power reception circuit between a first power reception value and a second power reception value.

12. The circuit of claim 11 further including:

a rectifying element; and

a second node Vr electrically connected to the node V1, wherein the rectifying element is electrically connected between the node V1 and the node Vr, wherein the rectifying element is configured to allow current to flow from the node V1 to the node Vr, and the rectifying element is configured to prevent current from flowing from the node Vr to the node V1.

13. The circuit of claim 12 wherein:

the antenna is a secondary coil of an inductive powering system; and

the rectifying element comprises a diode.

14. The circuit of claim 12 wherein the power reception circuit is configured to provide power to a charging circuit and an energy storage device.

15. A method for controlling the amount of power transferred between a master device and a slave device, comprising:

transmitting power from a primary antenna in the master device to a secondary antenna in the slave device;

receiving the power with a power reception circuit comprising the secondary antenna;

monitoring either a temperature or a current produced by the power reception circuit; and

controlling the power reception circuit to maintain the temperature or current between a high threshold and a minimum threshold.

16. The method of claim 15 wherein transmitting power from the primary antenna in the master device to the secondary antenna in the second device comprises transmitting power from a primary coil in the master device to a secondary coil in the second device.

17. The method of claim 15 wherein controlling the power reception circuit further comprises selectively tuning and detuning the power reception circuit to maintain the temperature or current between a high threshold and a minimum threshold.