| 摘要 |
PURPOSE:To output surely a reset signal even if power is hitted by activating a discharge circuit in response to outputs of both a comparator circuit comparing an output of a constant voltage circuit with a reference value and another comparator comparing the said voltage with another reference value. CONSTITUTION:When an output voltage of a constant voltage circuit 26 drops with power supply hitted, an output of a comparator 29 goes to a low level, a discharge transistor (TR)25 is turned on to start discharging a capacitor 16. When an output of the constant voltage circuit 10 rises again, although the output of the comparator 29 goes to a high level, if the discharge is insufficient, because the output of a comparator 31 remains high, the discharge TR25 keeps the on-state. The output of the comparators 30, 31 is turned off sequentially in response to the voltage reduction at an output terminal 15, the capacitor 16 is charged again, the output of the comparators 31, 30 goes to a high level sequentially, a charging circuit 19 is activated to charge the capacitor again rapidly. |
