| 摘要 |
<p>PURPOSE:To obtain a large decision margin and to stabilize the operation of a deciding circuit by use of a subordinate power source, by driving a logical circuit by subordinate electric power obtained from a high-voltage source through a voltage dropping circuit, and deciding on the voltage drop across a high voltage source and then obtaining a reset signal. CONSTITUTION:A high-voltage source voltage V0 is set to 12V, and a subordinate power source voltage V0' is set to 5V. Resistances R2, R3, R4 and R5 are so selected that when V0=8V and V0'=5V, voltages VA and VC are equal to each other. Even if the high-voltage source voltage starts dropping by the occurrence of a fault, the subordinate power source voltage is still in normal operation, so a voltage comparator IC2 and a logical circuit IC1 are still in normal operation. When the high-voltage source voltage drops below 8V, the comparator IC2 generates an output to reset the logical circuit IC1.</p> |
