SWITCHING POWER SUPPLY CIRCUIT AND ITS CONTROL METHOD

摘要

A switching power supply circuit realizing both reduction of the power consumption and shortening of the reset time and quickly dealing with the change from a stand-by state to an overload state. The switching power supply circuit comprises a transformer having a core containing an amorphous magnetic material, a switching element for flowing current through the primary-side winding of the transformer according to the drive signal, an output circuit for producing an output voltage according to the voltage induced in the secondary-side winding of the transformer, and a control circuit for generating the drive signal according to the current flowing through the primary-side winding of the transformer and the output voltage of the output circuit and switching among a normal operation mode, a normal standby mode, and a complete standby mode according to the output current of the output circuit or a mode switching signal supplied from outside.