| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To shorten time up to beginning of lighting, and suppress abnormal heat generation at resistors of a boosting circuit at regular lighting. <P>SOLUTION: Direct-current voltage outputted by a rectifying circuit 2 is converted into high-frequency alternating-current voltage by an inverter circuit 3, boosted by a transformer T1, and supplied to an igniter circuit 4. The igniter circuit 4 is structured of a voltage doubler circuit 6 supplying high voltage to a discharge lamp 1 at start of lighting and a circuit by which alternating-current voltage outputted by the inverter circuit 3 is supplied to the discharge lamp 1 through a capacitor C7, with a resistor R1 and a PTC thermistor P1 connected to one end of the voltage doubler circuit 6. Since, at start of lighting, temperature of the PTC thermistor P1 is low with a low resistance value, the high voltage boosted by the voltage doubler circuit 6 is supplied to the discharge lamp 1 without being lowered, and, since, at regular lighting, temperature of the PTC thermistor P1 rises to have a resistance value increased, no such problems occur that the resistor R1 or the like generates heat. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
