LIGHTING DEVICE FOR DISCHARGE LAMP

摘要

PURPOSE:To prohibit the lighting of a discharge lamp even after a DC power supply is once turned off and then resetting again in the turn-off state of the discharge lamp by signal switch when the discharge lamp can be reliably turned on or off under the state where the voltage of the DC power supply is being applied to a transistor inverter in a device for turning on the discharge lamp by a high frequency voltage converted by the transistor inverter. CONSTITUTION:A base current is supplied to a main transistor 6 for a certain duration through diodes 32 and 33 which are connected in series but reversely in parallel to a start capacitor 21 of an oscillating start timer circuit 18. Also, oscillation and start prevention means made of a signal circuit 29, a control transistor 27 and a diode 30 is provided, which is capable of turning on the control transistor 27 by a signal switch 35 before an oscillating and start current flows to the main transistor 6 through the oscillating and start timer circuit 18 from a DC power supply 1 after a power supply switch is turned on.