| 摘要 |
<p>PURPOSE:To prevent erroneous operation of electronic machinery due to reckless driving of a microcomputer by resetting the microcomputer even when the operation point of a comparator rises and voltage drops due to instantaneous power interruption by sustaining the voltage across a resistor through a capacitor provided to the first resistor. CONSTITUTION:A capacitor C3 is connected between both terminals 2, 3 of the first resistor R1 in parallel through. When a main power supply of AC 100V is turned ON, a drive power supply of 5V is supplied to a power supply Vcc for a detection circuit. Source voltage through the resistor R1 is supplied to the positive terminal 1a of a comparator 1 and a reference voltage through a fourth resistor R4 is inputted to a negative terminal 1b and two voltages are compared. When the main power supply is instantaneously interrupted and the source voltage Vcc drop below a rated voltage, the set value of a reference power supply due to a parallel circuit 11 rises and the operation point of the comparator 1 rises and, at the point of time when voltage drops to about 4.85V, reset operation takes place.</p> |
