Battery charging and testing circuit

摘要

A constant current battery charging circuit is provided by which the battery receives a full charge until the battery voltage reaches a threshold. When the battery voltage is above the threshold, the battery receives a trickle charge. The actual battery voltage is compared with a reference voltage to determine whether the full charge circuit should be in operation. Hysteresis is provided for preventing a rapid on/off operation around the threshold. The reference voltage is compensated for temperature variations. The hysteresis system and temperature compensation system are independent of each other. A separate test circuit is provided for testing the battery voltage. During testing of the battery, the full charge circuit is inoperative.