Patent ID: 8084886

Claim:
An uninterruptible power supply device, characterized by having an AC/DC converter that converts input alternating current power to direct current power and outputs the power to a load; a diode that is inserted between the output side of the AC/DC converter and the load; a battery that is connected to the cathode of the diode and outputs charged direct current power when the direct current power output of the AC/DC converter is cut; protection circuits that detect an overcurrent or overvoltage of the AC/DC converter and stop operation of the AC/DC converter; an input monitoring circuit that monitors the alternating current input of the AC/DC converter and outputs an alternating current input monitor signal; an output monitoring circuit that is connected between the AC/DC converter and the diode, and monitors the direct current output of the AC/DC converter and outputs a direct current output monitor signal; and a reactivation circuit that outputs a reset signal to the protection circuits so as to reactivate the AC/DC converter when the reactivation circuit determines the state in which the alternating current input is present and the direct current output is not present based on the alternating current input monitor signal and the direct current output monitor signal upon turn-on of the alternating current power.