| 摘要 |
PROBLEM TO BE SOLVED: To control the output of a DC/AC converter. SOLUTION: Switches S1 and S2 of a power switch 1 connected to a switching power supply 3, which is a voltage resonance type DC/AC converter via an inductor 2 are driven to be alternately turned on and turned off. A voltage detection circuit 4 detects the output voltage of the switching power supply 3, and the detection output is supplied to a control circuit 5 (IC) which controls the turning on/off of the power switch 1. The power switch 1 is controlled intermittently by the pulse signal of a PWM 5B of the control circuit 5 so as to obtain a constant AC signal or a rectified DC voltage from the switching power supply. The inductor 2 which is the component of the switching power supply 3 is used in common as a part of a down converter, and since the switching period and the on/off period of the power switch are synchronized with each other, a constant voltage can be o utputted for a DC voltage Vin of wide range with a simple circuit. |
