PURPOSE: To improve an output characteristic when energy is supplied to a load different from load characteristic, by using the detection information of an output voltage at a constant voltage load and an output current at a constant current load to drive the primary winding of a transformer.

CONSTITUTION: A power source E is turned on and off by a transistor TR1 which is driven by a control driving circuit simultaneously with the turning-on of a switch S1, and the voltage is boosted by a transformer T to obtain high voltage outputs in secondary windings W2 and W3. These outputs are smoothed (D1, C1 and D2, C2) and are applied to loads L1 and L2. The load L1 is driven with a constant voltage by a scotron charger, and the constant voltage output is divided by resistors R1 and R2 and is connected to the control driving circuit. Meanwhile, the load L2 is driven with a constant current by a corotron charger, and a current detector consisting of a resistance R6 and a capacitor C3 detects a returning current and outputs it to the control driving circuit. Thus, the output characteristic in case of energy supply to loads different from load characteristics is improved even if there is the variance of parts.