| 摘要 |
A voltage detection circuit for detecting an input voltage larger in absolute value than a power supply voltage is disclosed. This circuit comprises a first transistor connected between a terminal supplied with the input voltage and a circuit node, and a second and a third complementary transistors connected in series between the circuit node and a reference potential terminal. The first transistor is used as a voltage-dropping means, and the gates of the second and third transistors are commonly supplied with the power supply voltage. When the potential difference between the circuit node and the gate of the second transistor exceeds the threshold value of the same transistor, the second transistor is turned ON and the potential at the connection point of the second and third transistors begins to change. At this time, the input voltage is higher in absolute value than the power supply voltage because the first transistor operates as the voltage-dropping means.
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