| 摘要 |
PURPOSE:To prevent the flow of an overcurrent through a resonance circuit by making the drive control of each of switching elements in the active region thereof so as to form a resistance factor of large value when one of the switching elements is electrified while each of the filaments of an electric discharge lamp is low in temperature. CONSTITUTION:A drive control circuit 1 makes the drive control of at least one of switching elements Q1, Q2 in the active region thereof so as to form a resistance factor of large value when at least one of the switching elements Q1, Q2 is electrified while each of the filaments F1, F2 of an electric discharge lamp(l) is low in temperature. An overcurrent flowing through a resonance circuit when each of the filaments F1, F2 of the electric discharge lamp(l) is low in temperature immediately after the application of d.c. power to the lamp can thus be prevented by the resistance factor formed through the operation of one of the switching elements Q1, Q2 in the active region thereof, so that a stable-level preheating current can be obtained without causing even an instantaneous flash of the electric discharge lamp(l) at the time of applying the power to the lamp. |
