| 摘要 |
<p>PURPOSE:To secure sufficient reset time and to prevent a microprocessor from malfunctioning by forcibly grounding a connection point when a DC power voltage drops momentarily below a permissible level. CONSTITUTION:When the voltage at a terminal drops below a lower-limit set value at time (t), a waveform 33 is applied to a detecting circuit 8 to obtain an output waveform 34, and an output waveform 35 is also obtained from a switch circuit 9. A resistor 10 has a reference resistance value, so a capacitor 3 is discharged momentarily to the ground level. After the voltage at the terminal 5 starts recovering, the grounded state of the capacitor 3 is released at time t2, and the discharge is restarted through a resistance 2 to obtain a waveform 36. Namely, the potential at a connection point 6 starts rising at t2, and time tr up to a rise to a threshold level 37 is secured as reset time, thereby restarting normal operation thereafter.</p> |
