| 摘要 |
PURPOSE: To reduce stress applied at the time of preheating and starting an electric discharge lamp and in a no-load condition, by providing an inverter circuit composed of two switching devices, connecting a transformer to both ends of one of the switching devices in parallel, and connecting a resonance circuit to both ends of the secondary winding of the transformer in parallel. CONSTITUTION: A pulsating voltage V1 is obtained by full-waverectifying the voltage E of an AC power source after causing it to pass through a filter circuit 1 and a rectifier DB1. A transformer T2 is connected to both ends of a switching device Q1 in parallel. And a rectangular high-frequency voltage is applied to the primary winding n1 of the transformer T2 by turning the switching devices Q1, Q2 on and off interchangeably. A rectangular voltage transformed to a voltage its winding ratio times as high as the voltage is generated in the secondary winding n2 of the transformer T2, and is applied to a series resonance circuit composed of an inductance element L3 and the preheating capacitor C6 of an electric discharge lamp La connected in parallel to the secondary winding n2, and a sinusoidal-wavelike voltage is applied to the electric discharge lamp La. Accordingly, it becomes possible to reduce stress in a no-load condition. |
