| 摘要 |
PROBLEM TO BE SOLVED: To provide an input circuit that operates normally, without a through- current flowing therethrough, even when a circuit operated at a power supply voltage VCC1 or a circuit operated at a power supply voltage VCC2 higher than the power supply voltage VCC1 is connected to the input circuit. SOLUTION: The input circuit 1 is provided with an NMOS transistor(TR) N1 that protects a PMOS TR P2 and an NMOS TR N2 configuring an inverter IV1 against a voltage higher than a power supply voltage VCC1 applied to a pad 10; a PMOS TR P1 that pulls up a level of the gates of the PMOS TR P2 and the NMOS TR N2 to the power supply voltage VCC1; and a diode D1 that prevents a current from flowing from the pad 10 to the power source, with the voltage VCC1 via a resistive element R1 being a pull-up resistor, when a voltage higher than the power supply voltage VCC1 is applied to the pad 10.
|
