| 摘要 |
PROBLEM TO BE SOLVED: To suppress fluctuation of emission intensity and emission cycle of the discharge lamp due to the fluctuation of the battery voltage of the secondary battery while avoiding increase of loss and large size of the circuit and cost increase. SOLUTION: The drive signal modulation section 10 modulates the drive signal so as to reduce the difference of both signals by comparing the detection signal outputted by the capacitor voltage detection section 7 detected by the comparison section with the reference signal. Thereby, by modulating the drive signal, the output of the boosting section can be adjusted so that it may become lower when the voltage at both ends of the filter capacitor becomes higher, and, conversely, become higher when the voltage at the both ends of the filter capacitor becomes lower. As a result, the voltage at the both ends V0 of the filter capacitor C0 immediately before the start section starts operation is maintained at the prescribed value, and, thereby, the fluctuation of emission intensity and emission cycle of the discharge lamp due to the fluctuation of the battery voltage of the secondary battery can be suppressed, while avoiding increase of loss and large size of the circuit and cost increase. |
