| 摘要 |
PROBLEM TO BE SOLVED: To surely detect the turning on of a power supply voltage and to attain maintenance of an activating potential by comparing first and second monitor voltages, outputting a pulse signal corresponding to the detected result outputted from a power supply potential detecting circuit, making a power-on reset signal into activating potential corresponding to this signal, sensing the potential increase of a power source and generating the power-on reset signal. SOLUTION: A current flow via a resistor 111r of a first power supply potential monitor circuit 110 and the potential of a first monitor voltage, namely, the potential of a node N100 starts rising. Meanwhile, since a second power supply potential monitor circuit 120 serially connects three diode-connected N-channel transistors 121n, 122n and 123n between a power supply potential node and a node N120 to output a second monitor voltage, the potential of the node N120 maintains a ground potential for a while. When the potential of the power source becomes higher than the threshold voltage, the potential of nodes N131 and N132 to output the compared results A and B start rising.
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