Patent ID: 7557523

Claim:
A discharge lamp lighting device, comprising: a DC power source circuit; a smoothing capacitor connected to an output end of the DC power source circuit; an inverter main circuit adapted to convert a DC power output from the smoothing capacitor, to an AC power, and supply the AC power to a discharge lamp; a main control circuit adapted to control the inverter main circuit so as to control the AC power to be supplied to the discharge lamp; a timer circuit adapted to count a predetermined time; a power supply suppression section adapted to voluntarily suppress power supplied to the smoothing capacitor during a period where the timer circuit counts the predetermined time in an ON state of the discharge lamp; a voltage/voltage drop detection section adapted to detect a voltage or a voltage drop of the smoothing capacitor at least during a period where the power supplied to the smoothing capacitor is suppressed; a first comparator adapted to compare between a detection value of the voltage or the voltage drop of the smoothing capacitor and a first threshold value to determine a life end of the discharge lamp, and output a result of the determination; and an auxiliary control circuit adapted to perform a control operation depending on the output of the first comparator.