Patent ID: 10128762

Abstract:
A semiconductor device for power supply control includes an over-current detection circuit which detects an over-current state on a secondary side of a transformer by comparing a voltage in proportion to current flowing in a primary-side winding wire with an over-current detection voltage; a control signal generation circuit which generates a control signal to turn off a switching element when the over-current detection circuit has detected the over-current state; and an over-current detection level generation circuit which generates the over-current detection voltage in accordance with an on-duty of a driving pulse of the switching element. The over-current detection level generation circuit is configured to generate the over-current detection voltage in accordance with: Vocp=Vint+a·ON Duty, where Vocp represents the over-current detection voltage, ON Duty represents the on-duty, Vint represents the over-current detection voltage to be a reference, and “a” represents a correction coefficient.