| 摘要 |
PURPOSE:To provide a discharge lamp lighting, which can preclude the output voltage from getting too high at starting and light up a discharge lamp with a constant output once it is started. CONSTITUTION:When a discharge lamp FL is to be started, a capacitor of a timer circuit 3 bears no electric charges. Until the discharge lamp FL is lighted up, the condition of a transistor Q2 being turned on is kept, and a light emitting diode LED 1 is put on. Therewith a photo-transistor PTr1 is turned on to cause a current to flow in a resistance R13 is parallel connection with a resistance R12, and the gate voltage of a field effect transistor FET drops. This causes increase of electric charges to be accumulated by the drop of the synthetic capacitance of capacitors C6, C7, to quicken switching of a transistor Q1, and the output voltage of an inverter circuit drops. At the time of starting the discharge lamp FL, the output of the inverter 2 is sunk to prevent impression of a voltage exceeding a specified level. |
