A power supply circuit, including a rectifier circuit, an inductor having a voltage from the rectifier circuit applied thereto, a transistor for controlling a current flowing through the inductor, and an integrated circuit that performs switching of the transistor. The integrated circuit includes a signal generating circuit that generates a drive signal that reaches first and second logic levels to respectively turn on and off the transistor, a buffer circuit that generates first and second voltages for turning on and off the transistor based on the drive signal at the first and second logic levels, respectively, a detection circuit that detects elapse of a time period from when the drive signal reaches the first logic level to a predetermined timing before the drive signal reaches the second logic level, and a determination circuit that determines whether the terminal is short-circuited when the time period has elapsed since the drive signal reaches the first logic level.