Mems switching circuit and method for an implantable medical device

• US 20020095187A1
• Filed: 10/31/2001
• Published: 07/18/2002
• Est. Priority Date: 11/03/2000
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Greeninger, Daniel R., Thompson, David L.
• Granted Patent: US 6,804,552 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/3912 Output circuitry therefor, e.g. switches
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

An improved switching system for use with an implantable medical device (IMD) is described. The system utilizes Micro-Electrical-Mechanical system (MEMs) switches in place of one or more switches formerly implemented using transistor networks. Any type of switching circuit used within an IMD may be implemented using this technology. For example, MEMs switches may be utilized in a circuit for selectably delivering electrical stimulation to a patient, and/or in a circuit for providing surge protection. The fabrication of the MEMs switches may be performed using one or more separate tubs or wells on a silicon substrate to isolate switching circuitry from other IMD circuitry.

Claims

1. An implantable medical device (IMD), comprising:

a first circuit adapted to perform a first function;

a second circuit adapted to perform a second function; and

a switching circuit coupled to the first and second circuits to selectively electrically couple the first circuit to the second circuit, the switching circuit comprising at least one Micro-Electrical-Mechanical System (MEMs).

2. The MD of claim 1, wherein the first circuit comprises a circuit to supply electrical charge, and the second circuit comprises a circuit to deliver the electrical charge to a body.

3. The IMD of claim 1, wherein the first circuit comprises a source of electrical power.

4. The IMD of claim 3, wherein the second circuit comprises a circuit to receive the electrical power.

5. The IMD of claim 1, wherein the switching circuit includes a circuit to selectively electrically isolate the first circuit from the second circuit to prevent the second circuit from voltage surges experienced by the first circuit.

6. The IMD of claim 1, wherein the second circuit is adapted to provide at least one return current path for the first circuit.

7. The IMD of claim 1, wherein the Micro-Electrical-Mechanical System includes an activation mechanism that is electromagnetically activated.

8. The IMD of claim 1, wherein the Micro-Electrical-Mechanical System includes an activation mechanism that is thermally activated.

9. The IMD of claim 1, wherein at least one of the first and second circuits is adapted to provide high-voltage electrical stimulation to a body.

10. The IMD of claim 1, wherein the first circuit comprises multiple medical electrical leads, the second circuit comprises a circuit to generate an electrical signal, and wherein the switching circuit includes a circuit to route the electrical signal to the multiple medical electrical leads.

11. The IMD of claim 1, wherein the MD is implemented using a single integrated circuit die including multiple wells, and wherein at least one of the first and second circuit is implemented in one of the multiple wells, and the switching circuit is implemented using a different one of the multiple wells.

12. The IMD of claim 5, wherein the switching circuit is substantially suspended above the different one of the multiple wells.

14. The IMD of claim 13, and further including a control circuit coupled to the switching circuit to control the switching circuit such that the electrical stimulation is selectively provided to the patient.

15. The IMD of claim 14, and further including a surge protection circuit coupled to the first circuit.

16. The IMD of claim 15, wherein the surge protection circuit comprises a Micro-Electrical-Mechanical system (MEMs).

17. The MD of claim 13, wherein the MD is implemented using a single integrated circuit die including multiple wells, and wherein the first circuit is implemented in one of the multiple wells, and the switching circuit is implemented using a different one of the multiple wells.

18. The IMD of claim 17, wherein the switching circuit is substantially suspended above the different one of the multiple wells.

19. The IMD of claim 13, wherein the control circuit provides at least one electrical signal to control the switching circuit.

20. The IMD of claim 13, wherein the Micro-Electrical-Mechanical system includes an activation mechanism that is electromagnetically activated.

21. The IMD of claim 13, wherein the Micro-Electrical-Mechanical system includes an activation mechanism that is thermally activated.

22. The IMD of claim 13, wherein the switching circuit includes a MEMs switch to select a return current path.

23. The IMD of claim 13, wherein the first circuit is capable of delivering high-voltage electrical stimulation.

24. The IMD of claim 13, wherein the stimulation circuit includes a circuit to deliver high-voltage electrical stimulation.

25. The IMD of claim 13, wherein the Micro-Electrical-Mechanical system is a latching switch.

26. The IMD of claim 13, wherein the Micro-Electrical-Mechanical system is a momentary-contact switch.

28. The method of claim 27, wherein step b.) comprises generating an electrical control signal to close the MEMs switch.

29. The method of claim 27, wherein step b.) comprises generating an electromagnetic control signal to close the MEMs switch.

30. The method of claim 27, wherein step b.) comprises generating a thermal control signal to close the MEMs switch.

31. The method of claim 27, wherein the stimulation signal is a high-voltage stimulation signal.

32. The method of claim 27, wherein the stimulation signal is a pacing signal.

33. The method of claim 27, and further comprising utilizing a MEMs switch to select a return current path.

34. The method of claim 27, and further comprising:

detecting an electrical disturbance; and

utilizing a MEMs switch to manage the electrical disturbance.

36. The method of claim 35, and further comprising utilizing the first circuit to deliver power to the second circuit after the first and second circuits are selectively electrically coupled.

37. The method of claim 35, and further comprising utilizing at portion of the second circuit as a return current path for the first circuit after the first and second circuits are selectively electrically coupled.

38. The method of claim 35, wherein step (c) comprises electrically isolating the first circuit from the second circuit when a electrical disturbance is sensed in at least one of the first and the second circuits.

39. The method of claim 35, wherein step (c) comprises utilizing an electromagnetic signal to cause the MEMs to electrically couple the first and second circuits.

40. The method of claim 35, wherein step (c) comprises utilizing a thermal signal to cause the MEMs to electrically couple the first and second circuits.

41. The method of claim 35, and further comprising utilizing the first and second circuits to deliver electrical stimulation to a patient.

13. An implantable medical device (IMD), comprising

a first circuit that is capable of providing electrical stimulation to a patient;

and

a switching circuit coupled to the first circuit to selectively allow the electrical stimulation to be provided to the patient, the switching circuit comprising a Micro-Electrical-Mechanical system (MEMs).

27. A method of controlling delivery of electrical stimulation to a body, comprising:

a.) generating a stimulation signal; and

b.) utilizing a Micro-Electrical-Mechanical system (MEMs) switch to control delivery of the stimulation signal to the body.

35. A method of operating an implantable medical device, comprising:

(a) providing a first circuit adapted to perform a first function;

(b) providing a second circuit adapted to perform a second function; and

(c) utilizing at least one Micro-Electrical-Mechanical System (MEMs) to selectively electrically couple the first and second circuits.