DISCHARGE LAMP LIGHTING DEVICE AND PROJECTOR

摘要

A discharge lamp lighting apparatus comprising a d.c. power source section which rectifies and smoothes an a.c. voltage; a current detecting circuit which detects a current which flows through a discharge lamp; a power source ripple detecting circuit which detects a voltage change of power supplied from the d.c. power source section and outputs a voltage obtained by superimposing the detected voltage over a detected voltage which is available from the current detecting circuit; and a control circuit which controls, based on the output voltage from the power source ripple detecting circuit, an output voltage to the discharge lamp so that the current flowing through the discharge lamp becomes a constant current. A rate of superimposition of the output voltage from the power source ripple detecting circuit may be switched in accordance with the discharge lamp voltage.