| 摘要 |
PURPOSE:To enable the start of lighting adjustment by controlling either one of a voltage across the collector and the emitter of a switching transistor or the output voltage from an inverter constant so as to keep the no-load output voltages during full lighting time and lighting adjustment time at the same level. CONSTITUTION:At the time of a start lighting, either Vce, a voltage across a collector and an emitter detected by detection circuits 6 and 7 or V2, the secondary output voltage of an inverter is controlled at a constant by using a comparator VCO4. That is, the constants of a main circuit are set so that no-load voltage can retain a starting voltage even during lighting adjustment time. In this way, it is possible to start lighting adjustment even during lighting adjustment time. Further, under the loaded condition, the output current can be changed by changing the control value of Vce detection circuit 6 under certain controlled state through a full lighting/lighting adjustment switching signal, thus the switching between the full lighting and lighting adjustment can be controlled. |
