An input/output driving circuit may include a pad, an open-drain driving circuit, a high-voltage protection unit and a control unit. The pad is for transmitting and receiving signals. The open-drain driving circuit may output a transmission signal to the pad. The high-voltage protection unit may input a received signal from the pad. The control unit may control the open-drain driving circuit and the high-voltage protection unit. The control unit may include a gate control logic, a transmission control logic and an inverter. The gate control logic may receive a voltage of the pad and output a feedback voltage to the open-drain driving circuit. The transmission control logic may receive a clock signal and an enable signal, and transfer a first control signal to the open-drain driving circuit. The inverter may invert the enable signal and transfer an inverted enable signal to the gate control logic.