Patent ID: 7425802

Claim:
A discharge lamp lighting apparatus which is to be loaded with a plurality of types of high-intensity discharge lamps and connected with any one of the lamps to be lighted, the apparatus comprising: a power conversion circuit section that converts power supplied from a direct-current power source into alternating-current power to be supplied to a high-intensity discharge lamp; a lighting control circuit section that controls the supply power of the power conversion circuit section; and discriminator that determines a type of a connected high-intensity discharge lamp, wherein said discriminator determines the type of the connected high-intensity discharge lamp based upon a change rate of an electric characteristic of the high-intensity discharge lamp during a specific period, so that the connected high-intensity discharge lamp is lit with a desired electric characteristic selected based upon the determination result, the first change rate referring to a value obtained using a detection circuit to detect, at fixed time intervals, a shift of a voltage characteristic of the high-intensity discharge lamp with a time lapse during a prescribed time lapse after the voltage characteristic reaches a first voltage and then adding the detected values, or a value obtained by dividing the added value by the prescribed time.