04259639 is referenced by 54 patents and cites 1 patents.

A circuit is disclosed for providing automatic detection of end of life of a battery source, particularly a lithium iodine type battery source characterized by a sharply increased internal resistance characteristic near end of life. The circuit periodically samples the short circuit output current of the source, the sampling being done at a high switching speed and for an extremely short time duration so that power consumption is minimized and only the resistive component which causes the knee in the resistance characteristic is measured. In the embodiment as incorporated in a cardiac pacer device, detection of the internal resistance knee is utilized to cause a step change in an operating characteristic of the pacer, such as stimulus rate, whereby end of life can be accurately monitored.

Title
Circuit and method for detecting battery source end of life
Application Number
5/957475
Publication Number
4259639
Application Date
November 3, 1978
Publication Date
March 31, 1981
Inventor
Alexis C M Renirie
Nijmegen
NL
Agent
Woodcock Washburn Kurtz Mackiewicz & Norris
Assignee
Vitatron Medical
NL
IPC
G01N 27/42
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