| 摘要 |
PURPOSE:To form a device compact, reduce cost, and reduce power loss. CONSTITUTION:A voltage-down chopper circuit (b) comprising a switching element Q1, an inductance element L1, and a diode D1 is connected to an output end of a DC power supply (a), and a lamp filter circuit (c') comprising an inductance element L2 and a capacitance element C2 is connected to an output end of the voltage-down chopper circuit (b). A rectangular wave inverter circuit (d) comprising switching elements Q2-Q5 to supply a rectangular wave current to a discharge lamp DL is provided, and a control circuit X61 to perform on/off control of the switching elements Q1-Q5 is provided. Switching action of the switching elements Q2-Q5 is controlled in such a way that switching action of the switching element Q1 is temporarily stopped when polarity of the current through the discharge lamp DL is inverted, and that an accumulated energy emitting passage is formed between both ends of the inductance element L2 in a temporary stop period of the switching action of the switching element Q1. |
