| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of reliably holding a state in abnormality. SOLUTION: When voltage of a fluorescent lamp FL is raised caused by half-wave discharge, voltage of a condenser C7 is also raised, a condenser C8 is charged, a light emitting diode LED1 emits light by turning on a Zener diode ZD2, and a phototransistor Q6 is turned on. The output of an inverter circuit 1 is lowered by bypassing base current of a transformer Q1. Since electric potentials of the connecting points of a resistor R6 and a condenser C11 are high in a state where the inverter circuit 1 is not operated, the condenser C11 is charged through the resistor R6. Holding current is supplied from a DC power supply E and the condenser C11 to the Zener diode ZD2 through a diode D6, a state where the light emitting diode LED 1 emits light is maintained, and the on state of the phototransistor Q6 is maintained. Therefore, the fluorescent lamp FL is prevented from being flashed on and off caused by the operation of the inverter circuit 1, and stress is not generated on the fluorescent lamp FL. |
