| 摘要 |
A first voltage detection circuit detects whether a value of the power supply voltage is lower or higher than a first voltage, and generates a first signal according to the detection result. A second voltage detection circuit detects whether the power supply voltage is lower or higher than a second voltage higher than the first voltage, and generates a second signal according to the detection result. A control circuit receives the first and second signals, and conducts a control in such a manner that the control circuit ceases all the functions of an internal circuit when the first signal corresponds to a case where a value of the power supply voltage is lower than the first voltage, and ceases a part of the functions of the internal circuit when the first signal corresponds to a case where a value of the power supply voltage is higher than the first voltage and the second signal corresponds to a case where the value of the power supply voltage is lower than the second voltage. The first and second detection circuits have the same circuit constitution.
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