| 摘要 |
PURPOSE: To continuously rate an ignitor at a low cost by automatically supplying ignition pulse to a discharge lamp all times when the voltage of a power supply exceeds a preset level. CONSTITUTION: When a discharge lamp 12 is turned off, a circuit is connected to a main power supply. The voltage of the main power supply is accumulated in a voltage multiplier 18 at a preset coefficient. The voltage of the main power supply is applied to a voltage detector/regulator 20 to grant regulated power obtained from increased output voltage to an oscillator/trigger circuit 22 when the voltage of the main power supply exceeds a preset level. In this way, the oscillator is automatically started to give trigger pulse to a resonance circuit network 24. The circuit network 24 boosts the trigger pulse and applies the high voltage pulse to the discharge lamp 12 to cause ignition. When the ignition is achieved, discharge lamp load drops the input voltage of an ignitor 10 to a preset threshold value level or less for the voltage detector/regulator 20 with the output of the voltage multiplier 18. The ignition pulse is thus stopped. |
