Implantable lead-based sensor powered by piezoelectric transformer

• US 20040215279A1
• Filed: 04/25/2003
• Published: 10/28/2004
• Est. Priority Date: 04/25/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Christopherson, Mark A., Donders, Adrianus P., Leinders, Robert, Houben, Richard P.M., Deno, Curtis D.
• Granted Patent: US 7,203,551 B2
• Time in Patent Office: Days
• US Class Current: 607/35
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration

Abstract

In general, the invention is directed to an IMD having a piezoelectric transformer to power a lead-based sensor. The IMD powers the piezoelectric transformer with a low amplitude signal. The piezoelectric transformer serves to convert the voltage level of the low amplitude signal to a higher voltage level to drive the sensor produced by a battery in the IMD to voltage levels appropriate for IMD operation. A piezoelectric transformer offers small size and low profile, as well as operational efficiency, and permits the IMD to transmit a low amplitude signal to a remote sensor deployed within an implantable lead. In addition, the piezoelectric transformer provides electrical isolation that reduces electromagnetic interference among different sensors.

Claims

1. An implantable medical device comprising:

a battery to deliver a first voltage;

a piezoelectric transformer to convert the first voltage to a second voltage greater than the first voltage; and

a sensor powered by the second voltage.

2. The device of claim 1, further comprising an implantable lead, wherein the sensor is disposed within the lead.

3. The device of claim 1, further comprising an implantable lead, wherein the sensor and the piezoelectric transformer are disposed within the lead.

4. The device of claim 1, further comprising an input circuit to drive the piezoelectric transformer with an input signal.

5. The device of claim 2, wherein the piezoelectric transformer includes a first resonator that generates mechanical vibration in response to the input signal, and a-second resonator that generates an output signal in response to the mechanical vibration.

6. The device of claim 2, wherein the input signal has a frequency approximately equal to a resonant frequency of the first resonator.

7. The device of claim 1, wherein the device comprises one of an implantable pacemaker, an implantable cardioverter-defibrillator, an implantable neurostimulator, an implantable gastric stimulator, an implantable drug pump, and an implantable loop recorder.

8. The device of claim 1, wherein the first voltage is less than fifty percent of the second voltage.

9. The device of claim 1, wherein the first voltage is less than twenty percent of the second voltage.

10. The device of claim 1, wherein the sensor includes one of an ultrasonic sensor, an infrared sensor, and a camera.

11. The device of claim 1, wherein the second voltage is greater than or equal to 3 volts.

12. The device of claim 1, wherein the first voltage is less than or equal to 50 millivolts.

13. The device of claim 1, further comprising an implantable lead, wherein the sensor and the piezoelectric transformer are disposed within the lead, an input circuit to drive the piezoelectric transformer with an input signal, and conductors extending within the lead to electrically couple the input circuit to the piezoelectric transformer.

14. An implantable medical device comprising:

a battery to deliver a first voltage;

an input circuit to generate an input signal derived from the first voltage;

a piezoelectric transformer to convert the first voltage to a second voltage greater than the first voltage, wherein the piezoelectric transformer includes a first resonator that generates mechanical vibration in response to the input signal, and a second resonator that generates an output signal in response to the mechanical vibration;

a sensor powered by the second voltage; and

an implantable lead, wherein the sensor is disposed within the lead.

15. The device of claim 14, wherein the piezoelectric transformer is disposed within the lead.

16. The device of claim 14, wherein the input signal has a frequency approximately equal to a resonant frequency of the first resonator.

17. The device of claim 14, wherein the device comprises one of an implantable pacemaker, an implantable cardioverter-defibrillator, an implantable neurostimulator, an implantable gastric stimulator, an implantable drug pump, and an implantable loop recorder.

18. The device of claim 14, wherein the first voltage is less than fifty percent of the second voltage.

19. The device of claim 14, wherein the first voltage is less than twenty percent of the second voltage.

20. The device of claim 14, wherein the sensor includes one of an ultrasonic sensor, an infrared sensor, and a camera.

21. The device of claim 14, wherein the second voltage is greater than or equal to 3 volts.

22. The device of claim 14, wherein the first voltage is less than or equal to 50 millivolts.

23. An implantable medical lead comprising:

a lead body;

a piezoelectric transformer within the lead body; and

a sensor within the lead body and electrically coupled to the piezoelectric transformer,

wherein the piezoelectric transformer includes a first resonator that generates mechanical vibration in response to an input signal, and a second resonator that generates an output signal in response to the mechanical vibration, and the sensor is powered by the second voltage.

24. The device of claim 23, wherein the sensor includes one of an ultrasonic sensor, an infrared sensor, and a camera.

25. A method comprising:

converting a first voltage to a second voltage with a piezoelectric transformer, wherein the second voltage is greater than the first voltage; and

applying the second voltage to a sensor within an implantable medical device.

26. The method of claim 25, wherein converting the first voltage to a second voltage includes driving a first resonator of the piezoelectric transformer with a first signal to generate mechanical vibration, and transducing the mechanical vibration with a second resonator of the piezoelectric transformer to produce a second signal with the second voltage.

27. The method of claim 25, wherein the sensor is disposed within an implantable lead.

28. The method of claim 27, wherein the piezoelectric transformer is disposed within the lead.

29. The method of claim 27, wherein the device comprises one of an implantable pacemaker, an implantable cardioverter-defibrillator, an implantable neurostimulator, an implantable gastric stimulator, an implantable drug pump, and an implantable loop recorder.

30. The method of claim 25, wherein the sensor includes one of an ultrasonic sensor, an infrared sensor, and a camera.