Method and apparatus for determination of end-of-service for implantable devices

• US 5,344,431 A
• Filed: 09/14/1992
• Issued: 09/06/1994
• Est. Priority Date: 01/22/1990
• Status: Expired due to Term

• Current Assignee: Daniel W. Latham, Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Howard, William G., Thompson, David L., Merritt, Donald R., Skarstad, Paul M., Nichols, Lucy M., Roline, Glenn M., Weiss, Douglas J., Wyborny, Paul B.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Parker, Marianne
• Application Number:
  US07/944,872
• Time in Patent Office: 722 Days
• Field of Search: 128/419 P, 128/419 PG, 128/419 PS, 128/419 PT, 128/903, 607/9, 607/33, 607/34, 607/27, 607/29, 429/224
• US Class Current: 607/29
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A method and apparatus for determination of battery end-of-service in a medical device in which the medical device comprises a cathode limited electrochemical cell having an active metal anode and a manganese dioxide cathode and means for digital telemetry of cell voltage. The sloped, well defined voltage curve of such a cell during cell discharge combined with precise information available through digital telemetry allows for improved determination of battery end-of-service for the medical device.

Claims

1. A medical device having battery end-of-service indication comprising:

(a) an implantable housing;

(b) a medical device within said implantable housing,

(c) a cathode-limited electrochemical cell having an active metal anode and a manganese dioxide cathode within the housing;

(d) analog voltage measurement means within the housing for measuring a voltage of the electrochemical cell;

(e) analog-to-digital conversion means within the housing for converting the measured analog voltage into a digital signal; and

(f) telemetry means within the housing for telemetry of the digital signal.

2. A medical device according to claim 1 wherein the active metal anode is lithium.

3. A medical device according to claim 2 wherein a capacity ratio of lithium anode to manganese dioxide in the cathode limited electrochemical cell is in a range of about 1.0 to about 1.5.

4. A medical device according to claim 1 wherein telemetry of the digital signal is accomplished by pulse position modulation.

5. A medical device according to claim 1 wherein telemetry of the digital signal includes means for multiple voltage data transmission and means for error detection.

6. A method for determining battery end-of-service for implantable medical device comprising:

(a) providing a cathode limited electrochemical cell having an active metal anode and a manganese dioxide cathode in an implantable medical device;

(b) measuring a voltage of the cathode limited electrochemical cell in analog form;

(c) converting the analog voltage measurement into a digital signal; and

(d) transmitting the digital signal from the implantable medical device.

7. A method according to claim 6 wherein the step of providing an electrochemical cell includes the step of providing a lithium anode.

8. A method according to claim 7 wherein the step of providing an electrochemical cell includes the step of providing lithium anode and manganese dioxide cathode in the electrochemical cell in a capacity ratio of lithium to manganese dioxide in the cell in a range of about 1.0 to about 1.5.

9. A method according to claim 6 wherein the step of transmitting of the digital signal is accomplished by pulse position modulation.

10. A method according to claim 6 wherein the step of transmitting the digital signal includes transmitting the digital signal at least twice with error detection comparison of the transmitted digital signals.