Switch controller, switch control method, and power supply device comprising the switch controller

The present invention relates to a switch controller, a switch control method, and a power supply device using the same. The switch controller controls the switching operation of a power switch and receives a sensing voltage generated in a sensing resistor in which drain current flowing into the power switch flows. The switch controller uses the sensing voltage, and a lamp signal having the same cycle as a switching cycle of the power switch to generate a sum signal. The switch controller detects a change in the inclination of the sum signal to determine whether the sensing resistor is shorted. [Reference numerals] (300) Inclination detection unit;(400) Ocillator;(500) PWM control unit;(600) Gate driving unit