SWITCHING POWER SUPPLY AND AC ADAPTER USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a switching power supply which can reduce power loss depending on various load conditions.;SOLUTION: A switching power supply for controlling an FET5 with the PWM system comprises an output power detecting circuit 10 for detecting an output power of the switching power supply and an oscillation frequency control circuit 11 for controlling the oscillation frequency of the PWM control circuit 8 based on a control signal from this output power detecting circuit 10. The oscillation frequency control circuit 11 continuously lowers the oscillation frequency with transition to a light loading condition from a heavy loading condition based on the control signal from the output power detecting circuit 10.;COPYRIGHT: (C)2001,JPO