Patent ID: 8384373

Claim:
An alternating-current line signal detection device comprising: a semiconductor integrated circuit; and a conversion section adapted to rectify an alternating-current line signal and convert the rectified signal to an input signal to be fed to the semiconductor integrated circuit, wherein the semiconductor integrated circuit includes a monitoring section adapted to divide the alternating-current line signal into a plurality of voltage ranges with at least one reference voltage proportional to the amplitude of the alternating-current line signal to monitor within which voltage range the alternating-current line signal falls, a measuring section adapted to measure a duration for which the alternating-current line signal remains in each of the voltage ranges, and a determination section adapted to determine, based on the monitoring result of the monitoring section and the measurement result of the measuring section, whether the duration for which the alternating-current line signal remains in each of the voltage ranges exceeds a set time which can be set in advance to make a pass/fail determination on the alternating-current line signal.