Patent ID: 7332868
Filing Date: 2008-02-19
Classification: H05B

Abstract:
1. A discharge lamp lighting device that lights a discharge lamp having a pair of main discharge electrodes facing each other, comprising: a power supply circuit which supplies power to the discharge lamp; a current control element circuit which reduces a current flowing through the discharge lamp; and a current reduction modulation control circuit to which an output current modulation instruction signal is input, wherein the power supply circuit includes an output current detecting unit which detects an output current of the power supply circuit to generate an output current detecting signal, and wherein when the output current modulation instruction signal Sq is in an inactive state, the current reduction modulation control circuit controls the current control element circuit not to substantially restrict the current, and when the output current modulation instruction signal is in an active state, the current reduction modulation control circuit controls the current control element circuit such that the output current detecting signal is substantially equal to a value obtained by multiplying, by a proportional constant, the output current detecting signal obtained when the output current modulation instruction signal is activated.