| 摘要 |
PURPOSE:To cope with a instantaneous drop in source voltage and to set a decision voltage by separating a resistance for setting the input voltage to a voltage comparator from a semiconductor substrate, and providing one more capacitor for voltage holding. CONSTITUTION:The voltage VD obtained by dividing the source voltage VDD through polysilicon resistances 15 and 16 and the voltage VR obtained by dividing the voltage which drops from the source voltage by VF across a diode through resistances 13 and 14 are applied to a comparator 17. When the VDD drops, an external capacitor 12 which is charged up to (VDD-VF) is inhibited by the diode 11 from being discharged to a power terminal 01, so the VR is equal to the voltage value obtained by dividing the voltage value of the discharge through the series resistances of said polysilicon resistances 13 and 14. Therefore, if the VD drops below the VR held in the external capacitor 12, the output of the comparator 17 is inverted to drive the latch consisting of NAND circuits 18 and 19, and the latch output 05 goes up to ''H''.
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