BATTERY VOLTAGE DETECTING DEVICE AND METHOD

摘要

PROBLEM TO BE SOLVED: To precisely detect the voltage of a battery. SOLUTION: A pair of serially connected capacitors 28 and 29 is connected to a battery unit 11a to be detected for voltage through a first switch 21, and the voltage of the battery unit 11a is applied to each capacitor 28 or 29 by ON of the first switch 21. Thereafter, a second switch 22 is ON to fix the potential of the connecting point of each capacitor 28 or 29 to the reference potential of a voltage detecting means. A fourth switch 24 is also ON to fix the voltage of each input terminal of a differential amplifier 25. A third switch 23 is ON in such a state, and the fourth switch 24 is then OFF to apply the voltage of each capacitor 28 or 29 to the differential amplifier 25.