DISCHARGE LAMP LIGHTING DEVICE

摘要

PURPOSE:To reduce peak value variation and to realize a low noise by providing an impedance element for continuously feeding an electric current to a discharge lamp when a switching element is off so as to continuously feed a current to the lamp via the impedance element. CONSTITUTION:An impedance element Z1 is connected in parallel to a switching element SW and when the element SW is turned on by a drive signal a power source voltage E is applied to a lamp 1. In the case where the element Z1 is of such resistivity and inductivity as not to increase a lamp current IL, turning-on of the element SW increases the current IL and turning-off thereof applies a voltage to the lamp 1 via the element Z1 to flow a gradually reducing current. When the impedance element Z1 is capacitive, storing of energy in the element Z1 reduces a current thereto and the lamp current IL becomes a gradually reducing waveform similarly. Accordingly, a high frequency component is reduced to reduce generation of a noise.