| 摘要 |
PURPOSE:To provide a discharge lamp lighting device capable of preventing a rush current without reduction of an efficiency or temperature rise. CONSTITUTION:A full-wave rectification circuit 11 of two thyristors Th2, Th3 and two diodes D3, D4 is connected with a commercial AC power supply E. A zero-cross circuit 12 is connected with gates of the thyristors Th2, Th3. An inverter circuit 3 for lighting a discharge lamp FL is connected through a capacitor C1 in the full-wave rectification circuit 11. The zero-cross circuit 12 outputs a trigger pulse after every zero cross of the commercial AC power supply E to turn on either thyristor Th2, Th3 for rectifying it similarly for a normal diode. When the power supply is turned on after exceeding the zero cross, the trigger pulse is not outputted before next zero cross, so a rush current is not generated, but the trigger pulse is outputted from the zero-cross circuit 12 after next zero cross for rectification as in a normal diode bridge. |
