| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem of the conventional voltage detection circuit in which: it may incur any malfunction during a period of time in which an external voltage is monitored. <P>SOLUTION: The present invention relates to a voltage detection circuit having: a voltage selection circuit for outputting a voltage corresponding to a power supply voltage as a first voltage; a detection voltage selection circuit for selecting either an external input voltage inputted from an external terminal or the first voltage in accordance with a first control signal and outputting the selected voltage as a comparative voltage; a reference voltage generation circuit for generating a reference voltage; a comparator for comparing the reference voltage with the comparative voltage and outputting a comparison result as a detection signal; and a control circuit which generates the first control signal in such a manner that the detection voltage selection circuit outputs either the first voltage or the external input voltage as a comparative voltage in a time dividing manner, and, when fluctuation of the first voltage is detected, generates the first control signal in such a manner that a detection target selection circuit outputs the first voltage as a comparative voltage. <P>COPYRIGHT: (C)2012,JPO&INPIT |
