| 摘要 |
PURPOSE:To surely start a discharge lamp by applying DC voltage to the discharge lamp for a fixed period sufficient to maintain an arc discharge, then applying rectangular voltage to it. CONSTITUTION:A discharge lamp starting circuit LS drives a relay RY1 to open a relay contact r1 and close relay contacts r2, r3 with the output of a timer circuit TM for a fixed period sufficient to maintain an arc discharge from the lamp start. The output of a signal oscillator OSC is stopped to be inputted to a frequency divider DIV, the base current is fed from a low-voltage DC power source voltage-dropped and full-wave rectified from a power source VS to transistors Q2, Q5 of a full-bridge inverter circuit 3, and DC voltage is applied to a discharge lamp La. After the fixed period elapses, the timer circuit TM is turned off, the relay RY1 is returned to close the contact r1 and open the contacts r2, r3, the full-bridge inverter circuit 3 is driven through inverter drivers ID3, ID4, and rectangular voltage is applied to the discharge lamp La. The discharge lamp La can be surely started. |
