| 摘要 |
<p>PURPOSE:To put a computer in normal operation even in case of a longer instantaneous interruption of a commercial AC power source when the constitution of the computer is small by detecting the output voltage level of a batch rectifying circuit part by using a comparator and sending out a power failure detection signal. CONSTITUTION:When the commercial AC power source is disconnected to lower the output of the batch rectification part and the voltage at the variable reed A of a variable resistor 14 drops below a division voltage generated by resistances 20 and 21, the output of the comparator 22 falls almost to 0V, a transistor 23 turns off, and the photodiode of a photocoupler 24 turns off, thereby sending out the power failure detection signal. If the load of a voltage converting circuit varies owing to the alternation of the constitution such as an increase or decrease in the memory capacity of the computer and an increase or decrease in the number of channels, the time when the output voltage of the batch rectification part drops at the time of a break of the AC commercial power source varies, so the time for sending out the power failure detection signal also varies at the same time. Therefore, when the computer mechanism is made small, the computer can be put in normal operation even in case of a longer instantaneous break of the commercial AC power source.</p> |
