Curtail device of standby state energy using frequence delay

摘要

The present invention relates to an RC time constant setting circuit for generating a reference frequency of a PWM generator, which is a switching control means of an AC adapter. In particular, the present invention relates to a detection for detecting whether a normal state or a standby state is based on a voltage applied to a reference voltage output terminal of a PWM generator. Means for switching off when it is determined to be in a normal state through the detecting means, and switching means that is turned on when it is determined as being in standby state by the detecting means, and a variable resistor whose resistance value is changed according to the on / off operation of the switching means. Means and a condenser having a predetermined capacitance for generating an RC resonant frequency together with the variable impedance means. Generation is made so that unnecessary switching behavior in standby Since it is not lost, power consumption can be reduced.