Patent ID: 6853213

Claim:
An input/output circuit comprising an output circuit, said output circuit comprising: a first series circuit including a first transistor and a second resistor disposed between an input/output pin and a power supply; a second series circuit including a second transistor and a second resistor connected serially between the input/output pin and a low-potential power supply; control means for turning one of the first and second transistors on and the other off, based upon a control sianal at the time of a signal output, in accordance with a logic value of a signal that is to be output from the input/output pin, thereby causing said first and second series circuits to operate as an output buffer; and an output drive circuit connected in parallel with said first and second series circuits connected between the high-potential power supply and low-potential power supply, an output of said output drive circuit being set in a high impedance state based upon the control signal at the time of a signal input.