| 摘要 |
<p>PURPOSE:To improve run safety, without continuing light-off state due to a temporary voltage variation, and continuing power supply while light on, by providing mis-lighting detecting circuit, a direct current input voltage detecting circuit, and a specific interrupting means. CONSTITUTION:A mis-lighting detecting circuit 20 which detects a mis-lighting state; a direct current input voltage detecting circuit 23 which detects whether a direct current input voltage is within the specified range or not: and an interrupting means 6, which stops the power supply to a discharge lamp 11 when the mis-lighting state of the discharge lamp 11 is detected and the direct current input voltage outside the specified range is detected, and which allows power supply upon reception of a signal indicating that the voltage has returned within the specified range, are provided in a lighting circuit 1 which lights the discharge lamp 11 by using a direct current power supply 2. Consequently, a temporary voltage variation of the power supply 2 does not keep a light-off state of the discharge lamp 11, and it supplies power to continue the lighting state as long as the lamp is on.</p> |
