Circuit and method for controlling luminous intensity of discharge lamps

摘要

A circuit and method for controlling a discharge lamp without auxiliary lamp(s) are disclosed. The discharge lamp is controlled in a warmed-up arc discharge state when, e.g., power generation of a vehicular alternator is detected. The discharge lamp is transferred from the warmed-up discharge state to an illumination arc discharge state when, e.g., an inner temperature of the discharge lamp has arrived at a predetermined value. The control of warmed-up discharge state is abruptly carried out when, e.g., the internal temperature of the discharge lamp is below the predetermined temperature. A time at which the discharge lamp is to be turned off is controlled according to the internal temperature of the other discharge lamp to be turned on.