Power supply device

摘要

A power supply device includes a converter, a rectifier circuit, a voltage cycle detection circuit, and a power supply cutoff signal output unit. The converter converts an AC voltage inputted from an external power supply to a DC voltage and outputs the DC voltage. The rectifier circuit rectifies the AC voltage inputted from the external power supply and outputs a rectified waveform voltage. The voltage cycle detection circuit detects a voltage cycle in which the rectified waveform voltage reaches a predetermined threshold value and, when the voltage cycle is detected to be longer than a predetermined cycle, outputs a voltage cycle abnormality signal. The power supply cutoff signal output unit outputs a power supply cutoff signal when the voltage cycle abnormality signal is inputted.

主权项

1. A power supply device comprising:
a converter which converts an AC voltage inputted from an external power supply to a DC voltage and outputs the DC voltage; a full-wave rectifier circuit which rectifies the AC voltage inputted from the external power supply and outputs a full-wave rectified waveform voltage; a voltage cycle detection circuit which detects a voltage cycle in which the full-wave rectified waveform voltage reaches a predetermined threshold value and, when the voltage cycle is detected to be longer than a predetermined cycle, outputs a voltage cycle abnormality signal; and power supply cutoff signal output means for outputting a power supply cutoff signal when the voltage cycle abnormality signal is inputted, wherein the voltage cycle detection circuit includes:
a first voltage detector which outputs a first signal when the full-wave rectified waveform voltage of the full-wave rectifier circuit is detected to be not less than the predetermined threshold value,a first time period detector which outputs a first confirmation signal when the first signal continues to be outputted for a predetermined first time period or longer,a second voltage detector which outputs a second signal when the full-wave rectified waveform voltage of the full-wave rectifier circuit is detected to be less than the predetermined threshold value, anda second time period detector which outputs a second confirmation signal when the second signal continues to be outputted for a predetermined second time period or longer and outputs the voltage cycle abnormality signal when one of the first confirmation signal and the second confirmation signal is inputted.