Discharge lamp lighting circuit with lighting condition detector

摘要

A discharge lamp lighting circuit which, when a discharge lamp is removed from a connecting member such as a socket or the like and the discharge lamp is judged unlighted, stops the power supply to the discharge lamp to thereby prevent ill effects caused by the wrong detection of connecting condition detect means used to detect a connecting condition between the discharge lamp and connecting member. The discharge lamp lighting circuit comprises lighting control which supplies an electric power to a discharge lamp through a given connecting member (such as a socket or the like) and controls the lighting of the discharge lamp, a lighting condition detector which is used to detect the lighted or unlighted condition of the discharge lamp, a connecting condition detector which detects whether the discharge lamp is connected to the connecting member or not, and a power supply control which controls the supply of power to the discharge lamp. When the power supply control receives from the connecting condition detector a signal indicating that the discharge lamp is removed from the connecting member and also receives from the lighting condition detector a signal indicating that the discharge lamp is in the unlighted condition, the power supply to the discharge lamp is stopped.