Patent ID: 7573304

Claim:
An input/output circuit comprising: an output terminal; a first transistor driving the output terminal based on a predetermined signal, the first transistor having a gate electrode, and first and second electrodes; a second transistor controlling a potential of the gate electrode of the first transistor, the second transistor having a gate electrode, and first and second electrodes; a bias circuit generating a bias voltage for controlling the second transistor based on a level of the predetermined signal, and impressing the bias voltage to the gate electrode of the second transistor; and a third transistor switching a voltage which is impressed to the gate electrode of the second transistor based on a potential of the output terminal, the third transistor having a gate electrode, and first and second electrodes, wherein the first electrode of the second transistor is electrically connected to the gate electrode of the first transistor, and the second electrode of the second transistor is electrically connected to the output terminal and the second electrode of the first transistor through a resistor, and to the gate electrode of the third transistor, and wherein the gate electrode of the second transistor is connected to the bias circuit and the second electrode of the third transistor.