| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device which can detect easily a value of power supply voltage in an arbitrary timing under operation of an ordinary circuit. SOLUTION: The semiconductor device 10a has a voltage variation detection circuit 12a connected to the same electric power supply which is connected to the ordinary circuit 11. The voltage variation detection circuit 12a comprises an inverting amplifier 13a, a switching element 14 connected to between input and output of the inverting amplifier 13a and a capacitive element 15 connected to input of the inverting amplifier 13a. Also, the ordinary circuit 11 is set in operating state, after making the switching element 14 into On state, and the switching element 14 is made OFF state in the arbitrary timing, the charge corresponding to the power supply voltage VcO is accumulated in the capacitive element 15 when the switching element is OFF state. After the ordinary circuit 11 is made into a stop state, a potential VDD of the power supply is set at the arbitrary value, the value of the power supply voltage Vc and the voltage value VcO supported by the capacity element 15 are compared by the inverting amplifier 13a. COPYRIGHT: (C)2008,JPO&INPIT
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