| 摘要 |
PURPOSE:To make it possible to facilitate pulse lighting in a simple circuit constitution by providing a plurality of standard voltage circuits for setting current values and providing a means to switch a plurality of standard voltages. CONSTITUTION:A comparator is provided inside an integrated circuit IC1, a lamp current is detected by resistant R13-R15 and converted into a voltage, which is inputted to one of the input terminals of the comparator, and a standard voltage set at a current setting part 14 is inputted to the other. The current setting part 14 is composed of a photo-transistors P1-P3, resistors R24-R32, and trimmer resistors VR1-VR4, and a lamp current can be selected and set by on/off of the phototransistors P1-P3. A discharge lamp can thus be lighted in a simple constitution, thereby the cost can be reduced and the size be compact. |
