Power supply control device and flyback converter

A power supply control device, used for a flyback converter, the flyback converter comprising:

• a switching element;
• a transformer, including a primary winding, a secondary winding, and an auxiliary winding;
• a rectifying element;
• and
• a smoothing capacitor, wherein
• an application end of an input voltage is connected to one end of the primary winding,
• a current inflow end of the switching element is connected to another end of the primary winding, and
• the rectifying element and the smoothing capacitor are disposed on a rear side of the secondary winding, wherein the power supply control device comprises:
• a comparator, comparing a current sensing signal generated by I/V conversion of a primary side current flowing in the primary winding with a threshold voltage;
• a switching controller, turning off the switching element according to a comparing result of the current sensing signal and the threshold voltage by the comparator;
• an external terminal, connectable to a connection node of an external resistor connected in series between one end of the auxiliary winding and an application end of a ground potential;
• a current detector, detecting a terminal current flowing through the external terminal;
• and
• a threshold voltage corrector, correcting the threshold voltage based on a current detection signal of the current detector.