| 摘要 |
PROBLEM TO BE SOLVED: To prevent erroneous output of an abnormal output, when there is a gradual change in primary side input voltage or repeated turning on/off of a control power supply. SOLUTION: A control power supply 1 supplies power to a load 2 (electronic circuit) in DC output voltage. In a monitoring circuit, a power supply voltage decrease detection part 3 detects decrease in DC 5 V voltage, and outputs an on/off signal; a timer circuit 5 continues timer operation with an output voltage decrease detection signal; and when the time is ended, confirms that the voltage decrease has continued for a fixed period of time; and with the time out, an abnormality output circuit 6 outputs an abnormal decrease in power supply voltage of the control power supply. Furthermore, a voltage decrease detecting circuit 7, upon detecting that an input voltage (DC 110 V) is not higher than the range of rated voltage, resets a timer operation of the timer circuit and locks the abnormality output circuit. The voltage decrease detecting circuit adds logically a voltage decrease detection output signal, as an on/off signal, to a detection output signal of the power supply voltage decrease detecting part 3. COPYRIGHT: (C)2011,JPO&INPIT
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