Integrated circuit and power supply circuit

Abstract

A power supply circuit that generates an output voltage from an AC voltage inputted thereto. The power supply circuit includes a rectifier circuit rectifying the AC voltage, an inductor receiving a rectified voltage from the rectifier circuit, a transistor controlling an inductor current flowing through the inductor, and an integrated circuit switching the transistor based on the inductor current and the output voltage. The integrated circuit includes a sample-and-hold circuit that samples-and-holds a voltage corresponding to the rectified voltage in a predetermined timing, an output circuit that outputs a limit voltage based on the voltage held by the sample-and-hold circuit, indicating a limit value for limiting the inductor current, and a signal output circuit that receives the limit voltage and a voltage corresponding to the inductor current, to thereby output a signal to turn off the transistor upon determining that a current value of the inductor current exceeds the limit value.