| 摘要 |
PROBLEM TO BE SOLVED: To provide a permission signal generation circuit capable of stably controlling the permission of light emission with simple circuit constitution. SOLUTION: The permission signal generation circuit 3 includes: a first comparator 14 outputting a first comparison signal V<SB>C1</SB>based on charge voltage and reference voltage of a discharge capacitor 9; a second comparator 15 outputting a second comparison signal V<SB>C2</SB>for controlling the on/off of the charge of the discharge capacitor 9 based on the charge voltage and reference voltage higher than that of the first comparator 14; and a detection circuit 16 having a bipolar transistor 17 turned on/off in accordance with the first comparison signal V<SB>C1</SB>and a thyristor 18 connected to the bipolar transistor 17 in series and turned on in accordance with the second comparison signal V<SB>C2</SB>and turned off in accordance with the transition of the bipolar transistor 17 to an off-state, and detecting that both the bipolar transistor 17 and the thyristor 18 are in an on-state and outputting it as a permission signal S<SB>3</SB>. COPYRIGHT: (C)2008,JPO&INPIT |
