SOURCE VOLTAGE FLUCTUATION DETECTING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a low-cost source voltage fluctuation detecting circuit which can be miniaturized. SOLUTION: A reset IC inside which a reset voltage is set is used as a voltage fluctuation detecting element 1 connected to a primary power line and outputting a detection signal when a source voltage V fluctuates. Since a zener diode ZD1 serving as a constant voltage element is connected between the point of connection of a light emitting element LED with a current-limiting resistance R3 and earth, the voltage applied to the output side of the voltage fluctuation detecting element 1 can be limited by the zener diode ZD1 .