| 摘要 |
PURPOSE:To prevent an erroneous operation, etc., by providing a DC voltage level detector, a charge/discharge switching circuit, a timer, and an AC voltage level detector. CONSTITUTION:A switching regulator 4 converts a DC voltage smoothed by a capacitor 3 into a DC or AC voltage to supply power to a load 5. A DC voltage level detector 6 monitors a DC voltage applied to the capacitor 3 to detect the generation of interruption of an AC power source 1, and operates a timer 9 if the interruption occurs. When the timer 9 is started, a charge/ discharge switching circuit 7 switches a battery 8 from a charging state to a discharging state. The timer 9 operates a predetermined time inhibitor 11 to inhibit control by the output of an AC level detector 10. The detector 10 monitors the voltage of the source 1. Thus, an erroneous operation is prevented to detect the interruption of the source 1. |
