MULTIOUTPUT SWITCHING POWER UNIT

PURPOSE: To stabilize multiple outputs by controlling the feedback quantity of a circuit in accordance with the fluctuation of DC output voltage, which feeds back AC output voltage to a DC input power source driving a switching circuit through conversion of AC output voltage to DC one. CONSTITUTION: The voltage set up at the secondary output windings 63-66 of a transformer 6 of a switching circuit 2 is rectified, smoothed and supplied to load RL. A feedback quantity control circuit 8 monitors specific DC output voltage and detects the quantity of voltage variations. When the DC output voltage raises, the reactance of a reactor winding 822 of a reactor 82 increases. As a result, the voltage applied to an input winding 91 of a feedback transformer 90 in a feedback circuit 9 drops. On that account, the feedback voltage becomes low. Consequently, the driving DC voltage of the switching circuit 2 becomes low. So does the output voltage of a transformer 6 for oscillation and outputting.