IMPLANTABLE MEDICAL DEVICE WITH INTERNAL PIEZOELECTRIC ENERGY HARVESTING

• US 20100317977A1
• Filed: 05/06/2010
• Published: 12/16/2010
• Est. Priority Date: 06/10/2009
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Piaget, Thomas W., Zhang, Cheng, Chavan, Abhijeet V., Maile, Keith R., Mi, Bin, Juffer, Lance E.
• Granted Patent: US 8,777,863 B2
• Time in Patent Office: Days
• US Class Current: 600/486
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: H02N 2/18 producing electrical output from mechanical input, e.g. generators for measurement devices G01
• CPC Class Codes: H10N 30/308 Membrane type

Abstract

Methods, systems, and apparatus for powering and/or recharging medical devices implanted within the body are described. An illustrative power generation module disposable within the interior space of an implantable medical device includes a module body that defines an interior cavity as well as a flexible diaphragm that spans the interior cavity. The flexible diaphragm includes a first electrical conductor, a piezoelectric layer disposed adjacent to the first electrical conductor, and a second electrical conductor disposed adjacent to the piezoelectric layer. The piezoelectric layer is configured to displace within the interior cavity and generate a voltage differential between the first electrical conductor and the second electrical conductor.

Claims

1. A power generation module disposable within the interior space of an implantable medical device, the power generation module comprising:

a module body defining an interior cavity;

a flexible diaphragm spanning the cavity, the flexible diaphragm including;

a first electrical conductor;

a piezoelectric layer disposed adjacent to the first conductor; and

a second electrical conductor disposed adjacent to the piezoelectric layer;

wherein the piezoelectric layer is configured to displace within the interior cavity and generate a voltage differential between the first electrical conductor and the second electrical conductor in response to a change in pressure within the interior cavity.

2. The power generation module of claim 1, further comprising a power conversion circuit that converts the voltage differential between the first and second electrical conductors into an operating current that can be used to power one or more components within the implantable medical device.

3. The power generation module of claim 1, wherein the flexible diaphragm further comprises:

an insulating layer disposed adjacent to the second electrical conductor;

a third electrical conductor disposed adjacent to the insulating layer;

a second piezoelectric layer disposed adjacent to the third electrical conductor; and

a fourth electrical conductor disposed adjacent to the second piezoelectric layer.

4. The power generation module of claim 3, wherein the flexible diaphragm has a neutral bending plane, and the insulating layer is positioned along the neutral bending plane.

5. The power generation module of claim 1, wherein an interior of the cavity is at reduced pressure relative to a pressure exterior to the cavity.

6. The power generation module of claim 1, further comprising a lower electrical conductor coupled to a lower surface of the cavity.

7. The power generation module of claim 6, further comprising a controller configured to selectively electrically disconnect the lower electrical conductor and the first electrical conductor.

8. The power generation module of claim 7, wherein when the lower electrical conductor is electrically disconnected, movement of the flexible diaphragm creates a voltage differential between the first electrical conductor and the second electrical conductor.

9. The power generation module of claim 7, wherein when the lower electrical conductor is electrically connected, movement of the flexible diaphragm creates a voltage differential between the lower electrical conductor and the first electrical conductor.

10. An implantable sensor for sensing one or more physiologic parameters, comprising:

a sensor module configured to sense one or more physiologic parameters;

a rechargeable power storage device;

the power generation module of claim 1, the power generation module electrically connected to the rechargeable power storage device; and

a power conversion circuit that converts the voltage differential between the first and second electrical conductors into an operating current for recharging the rechargeable power storage device.

11. A power generation module disposable within an implantable medical device, the power generation module comprising:

a module body defining a cavity including a lower surface and a cavity opening;

a flexible diaphragm spanning the cavity opening;

a piezoelectric assembly disposed adjacent to the lower surface, the piezoelectric assembly including;

a first electrical conductor;

a piezoelectric layer disposed adjacent to the first electrical conductor; and

a second electrical conductor disposed adjacent to the piezoelectric layer; and

a fluid disposed within the cavity.

12. The power generation module of claim 11, wherein the flexible diaphragm has a first diameter, the piezoelectric assembly has a second diameter that is less than the first diameter, and the module body includes a tapered rigid wall extending from a position at or near a periphery of the diaphragm to a position at or near a periphery of the piezoelectric assembly.

13. The power generation module of claim 12, wherein a pressure that is applied through the fluid onto the piezoelectric assembly is greater than a pressure exterior to the flexible diaphragm.

14. A power generating module configured to be electrically connected to an implantable medical device, the implantable power generating module comprising:

a housing having a first end, a second end, and a cavity disposed between the first end and second end;

a first flexible diaphragm disposed about the first end;

a second flexible diaphragm disposed about the second end;

a plurality of piezoelectric assemblies disposed within the cavity, each piezoelectric assembly configured to flex and generate an electrical operating current that powers one or more components of the implantable medical device in response to an external pressure applied to the first flexible diaphragm; and

a fluid disposed within the cavity.

15. The power generating module of claim 14, wherein each of the plurality of piezoelectric assemblies comprise a first electrical conductor, a second electrical conductor, and a piezoelectric layer disposed between the first and second electrical conductors.

16. A dual mode pressure sensor having a sensing mode and a power generating mode, the dual mode pressure sensor comprising:

a housing defining a top surface and a cavity, the cavity including a lower surface;

a first electrical conductor disposed adjacent to the lower surface;

a second electrical conductor disposed adjacent to the top surface;

a piezoelectric layer disposed adjacent to the second electrical conductor;

a third electrical conductor disposed adjacent to the piezoelectric layer; and

a controller configured to selectively switch the dual mode pressure sensor between a sensing mode in which at least one physiologic parameter is sensed and a power generating mode in which an operating current is generated for powering the dual mode pressure sensor.

17. The dual mode pressure sensor of claim 16, wherein the controller switches the dual mode pressure sensor to the sensing mode by electrically switching off the third electrical conductor and electrically switching on the first electrical conductor.

18. The dual mode pressure sensor of claim 17, wherein movement of the second electrical conductor relative to the first electrical conductor provides a capacitance indicative of a pressure change when the dual mode pressure sensor is in the sensing mode.

19. The dual mode pressure sensor of claim 16, wherein the controller switches the dual mode pressure sensor to the power generating mode by electrically switching off the first electrical conductor and electrically switching on the third electrical conductor.

20. The dual mode pressure sensor of claim 19, wherein movement of the piezoelectric layer provides a voltage differential between the first and second electrical conductors that can be captured to provide a charging current when the dual mode pressure sensor is in the power generating mode.

21. The dual mode pressure sensor of claim 16, wherein the piezoelectric layer is disposed between the second electrical conductor and the third electrical conductor.

22. A method of generating electrical power within a patient, the method comprising:

inserting an implantable medical device into the body of a patient, the implantable medical device including a power generation module disposed within the implantable medical device, the power generation module comprising;

a module body defining an interior cavity;

a flexible diaphragm spanning the cavity, the flexible diaphragm including;

a first electrical conductor;

a piezoelectric layer disposed adjacent to the first conductor;

a second electrical conductor disposed adjacent to the piezoelectric layer; and

power circuitry configured to convert a voltage differential between the first and second conductors into an operating current for powering one or more components of the implantable sensor;

operating the implantable medical device within a body lumen of the patient at a location that subjects the flexible piezoelectric layer to periodic pressure pulses, thereby causing a voltage differential between the first electrical conductor and the second electrical conductor; and

converting the voltage differential into an operating current for powering one or more components of the implantable medical device.