Fault-Tolerant Battery Monitor and Charger
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
A technique is described whereby a microprocessor-controlled switching circuit provides a means of detecting defective batteries, as used to retain data in memory arrays, allowing the defective batteries to be replaced without disturbing the accuracy of the non-volatile memory. In addition, the circuit provides a means of charging a battery and to indicate when a battery is to be replaced. Since a battery must be present in order to properly maintain data as written into computer memory data banks should primary power be lost, the circuit described herein provides assurance that five basic functions exist: 1. The battery is maintained at full charge while primary power is present. 2. The battery state is periodically tested at zero charge current, and a defective battery is detected. 3.