| 摘要 |
<p>PURPOSE:To realize a watch dog timer function and an instantaneous cut-off securing function by a simple circuit constitution, by providing a retrigger type monostable circuit which is triggered by a computer operating signal, a monostable circuit exclusive power source circuit, and a voltage monitoring circuit. CONSTITUTION:When a computer power source is supplied, capacitors 4, 6 and 33 are charged, and its output voltage becomes higher gradually. When a reset input signal of a computer reaches above a prescribed voltage, a computer operating signal is outputted, and a monostable circuit 1 is set. In case the power source of the computer is cut off instantaneously, its voltage drop state resets the monostable circuit 1 through a capacitor 37. When the titled circuit is constituted in advance so that the monostable circuit 1 is reset in a voltage range in which the power source of the computer drops but the computer can still be operated normally, by adjusting the values of resistances 35, 36, the monostable circuit 1 is reset at that time point, an output of the capacitor 4 is varied to an L level, and the computer becomes a reset state.</p> |
