| 摘要 |
PROBLEM TO BE SOLVED: To suppress irregular voltage rise of a smoothing capacitor and to start up a discharge lamp reliably by providing a control means for switching off both first and second switching elements when a load circuit is unloaded, for synchronizing fifth and sixth switching elements with the polarity of an alternator, and for switching on/off alternately. SOLUTION: In this device, a capacitor C2 is connected between an alternator Vs and a capacitor C1. When a load circuit is unloaded, the capacitor C2 suppresses irregular pressure rising of the capacitor C1 to restrict energy from the alternator Vs to flow in the capacitor C1. Regarding the capacitor C1 as a dc power supply, approximately a half-bridge inverter comprised of switching elements Q3 and Q4, an inductor L2, the capacitor C2 and the alternator Vs is formed and the alternator Vs is the one to replace a coupling capacitor. By the resonance effect of an LC series circuit comprised of the inductor L2 and the capacitor C2, a high pressure pulse is generated to actuate a discharge lamp. |
