POWER-SUPPLY APPARATUS FOR MONITOR

PROBLEM TO BE SOLVED: To enhance the efficiency of the electric power of a monitor with power consumption suppressed by a method wherein a power-factor correction circuit which cuts an operating power supply to be supplied to a controller at a switching power- supply circuit is installed according to a power-saving-function suppression circuit which responds to a power-saving signal in a power-saving mode. SOLUTION: When an AC power supply is applied to a power-supply apparatus, it is changed into a DC power supply by a rectifying circuit 10. The DC power supply is input to a power-factor correction circuit 50, and it is voltage-divided by first voltage-dividing resistor R7 , R8 so as to be supplied to a multiplier at a power-factor correction controller 51. In addition, the initial driving current of the power-factor correction controller 51 is supplied through a resistor R9 . Then, the power-factor correction controller 51 switches and controls a switching transistor Q3 at a switch means. On the other hand, when a power-saving signal is input to a switching transistor Q2 at a power-saving-function control circuit 30, the error amplifier output of the power-factor correction controller 51 is grounded, and the switching transistor Q3 is turned off so as to be maintained. Then, a mode power-supply circuit 40 is operated, and a power-saving mode is set.