DUAL USE THERMISTOR FOR BATTERY CELL THERMAL PROTECTION AND BATTERY PACK OVERCHARGE/UNDERCHARGE PROTECTION

摘要

A protection circuit (100) for use with a battery operated device (50) which includes an over temperature detector (110), a controller (130), and a voltage divider circuit (102 and 106). The voltage divider circuit includes a multi-use thermistor (102) for monitoring a temperature of a battery cell (104), a battery charger, or a battery operated device. Further, the thermistor can be operatively connected to the over temperature detector. An input voltage at the input (114) of the over temperature detector can vary relative to a variance in the monitored temperature. The temperature detector can signal the controller to terminate the charging of the battery cell if the temperature exceeds a predefined value. The device discharge detector can signal the controller to terminate the discharging of the battery cell if the battery operated device determines a specific event such as water intrusion, circuit failure or a software problem.