Discharge lamp lighting apparatus for controlling voltage of switching transistor by raising starting voltage.

摘要

A discharge lamp lighting apparatus of this invention includes an inverter circuit (20) and a control circuit (30) connected to a power source rectifier (14) for supplying a D.C. voltage. The inverter circuit (20) includes a parallel voltage resonance circuit of an output transformer (T1) and a resonance capacitor (C2) and the output side of the output transformer (T1) is connected to a discharge lamp (16) and a timer circuit (50). The inverter circuit (20) further includes a switching transistor (Q1) for switching the D.C. power source and a voltage detection circuit (40) for detecting a voltage VCE between the collector and emitter of the switching transistor (Q1). In the start-up operation of the discharge lamp (16), the control circuit (30) raises the control level of VCE of the switching transistor (Q1) so as to set the output voltage of the inverter circuit (20) high until it receives a signal which is output after a preset time determined by the timer circuit (50) has elapsed, and under this condition, the discharge lamp (16) is started.