| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge-lamp operating device which is constituted to prevent the application of stresses to parts, even when the device is initiated or the load of the device fluctuates, and at the time when the ambient temperature is high. SOLUTION: Higher harmonic components are reduced by making an input current to be continuously inputted even in a part where a pulsative current is close to zero, by supplying an electric current from a full-wave rectifier circuit 1, when the voltage of the circuit 1 is higher than the charging voltage of a capacitor C3 for charging, or superposing the resonance current of a second capacitor C2 and an inductor L1 upon the input current, when the voltage of the circuit 1 is lower than the charging voltage. When the output of an inverter circuit 3 increases due to the starting of a discharge-lamp operating device or the fluctuation of the load of the device, the output of the inverter circuit 3 is lowered by turning on a field effect transistor Q2 and short-circuiting the inductor L1 by turning on a Zener diode ZD1. The output of the inverter circuit 3 can be lowered surely, even when the output of the circuit 3 drops, because the resistance value of a thermistor R2 rises, and the voltage of the thermistor R2 rises against a resistor R1 when the thermistor R2 detects a temperature higher than a prescribed value. |
