| 摘要 |
PURPOSE:To stabilize the startability, particularly, to discharge lamp with high performance by changing the current or frequency to be outputted to a state different from steady state for a prescribed time after starting power source output when a plurality of loads are operated by use of a high frequency power source. CONSTITUTION:The AC voltage from a commercial power source VS is rectified by a full-wave rectifying circuit 2, converted into a smooth DC voltage by a voltage reducing chopper circuit 3, converted into a high frequency power by an inverter circuit of bridge structure in the latter stage, and supplied to a load 5. In the circuit 3, a low DC voltage is generated by a MOS transistor Q1, an inductor L2, and a capacitor C4, and in a chopper control circuit 32, the operating frequency or duty of the transistor Q1 is changed, whereby the output voltage of the circuit 3 is changed. An inverter circuit 4 is formed of a full bridge circuit consisting of MOS transistors Q2-Q5, and the frequency determined by a current circuit 42 is divided by the inverter circuit 41 to alternately switch the transistors Q2, Q5 and Q3, Q4. |
