POWER SUPPLY CONTROLLER AND INSULATED SWITCHING POWER SUPPLY

There is provided a power supply controller including: a monitor voltage generation part configured to generate a monitor voltage according to a primary voltage of a transformer that forms an insulated switching power supply; a sample/hold part configured to sample/hold the monitor voltage and output a feedback voltage; and a controller configured to turn on/off a primary current of the transformer by a fixed on-time method according to the feedback voltage, wherein the sample/hold part samples/holds the primary voltage at a plurality of different timings and outputs one of a plurality of hold values as the feedback voltage.