| 摘要 |
PURPOSE:To prevent the trouble or shortening of lifetime of a flash lamp by monitoring the voltage of a capacitor in charge and discharge circuits at timing corresponding to the fluctuation of the voltage and instantaneously inhibiting DC discharge generated due to an arbitrary cause regardless of pulse lighting. CONSTITUTION:When electricity is discharged from the state in which a capacitor 18 is charged at a set value, the first timing of the drop of the voltage of the capacitor is detected and decision timing is produced because the voltage is reduced and made lower than a reference value. When DC discharge is generated, the voltage of the capacitor 18 made lower than the reference value once and reduced is not returned and is kept as it is at a low level because charges to be charged to the capacitor 18 flow into a flash lamp 22 under a conductive state. Consequently, the state of the low level is discriminated at second timing after a fixed time passes after the first timing and DC discharge is detected, and charging is stopped. Accordingly, when DC discharge is generated immediately after pulse lighting, the DC discharge is stopped instantaneously, the flash lamp 22 is protected, and the shortening of the lifetime of the flash lamp is prevented. |
