| 摘要 |
PURPOSE:To prevent generation of such inconvenience as a momentary flashing of a discharge lamp caused by ON/OFF operation of a power source by applying no start-up high voltage to the lamp, in the case where the lighting-up start part of the lamp is controlled by an outside dimming signal, when the dimming condition signal is in the vicinity of the lowest brightness. CONSTITUTION:Power is supplied to a lamp start lighting part 1 by an AC power source AC via a power source switch SW, and the part 1 is controlled by a lighting control part 4 to supply power to a discharge lamp 2. The part 4 controls, on the basis of a control signal of a dimming signal from the outside received by a dimming signal receiving part 5, the output corresponding thereto with respect to the lighting part 1, to supply it to the lamp 2. A power supply reset signal generation part 3 detects ON/OFF of the switch SW and inputs a reset signal to the control part 4, but if the level of dimming signal is in the vicinity of the lowermost brightness level, generation of start pulse with respect to the lamp 2 is stopped. It is thus possible to prevent generation of such an inconvenience as a momentary flashing of the lamp 2 if the switch is put on/off under the above condition. |
