| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide means capable of monitoring a power supply state during a real system operation. <P>SOLUTION: A semiconductor integrated circuit comprises: an oscillator 14; a ring oscillator 11 having an oscillating frequency varying depending on a power supply voltage; an interval timer 13 measuring a predetermined determination period based on a signal of the oscillator 14; a frequency measurement counter 12 measuring an oscillating frequency oscillated by the ring oscillator 11 during the determination period; a nonvolatile memory 15 holding an upper limit value and a lower limit value of the oscillating frequency; and a voltage determination circuit 16 determining whether the oscillating frequency measured by the counter is within a range of a determination code of an upper limit voltage/lower limit voltage held by the nonvolatile memory 15 to output the determination result. <P>COPYRIGHT: (C)2013,JPO&INPIT |
