Patent ID: 7652518

Claim:
A bus switch with level shifting, comprising: a first terminal configured to receive and output a first signal having an amplitude of a first power supply voltage higher than a reference voltage; a second terminal configured to receive and output a second signal having an amplitude of second power supply voltage higher than the first power supply voltage; an output control terminal to which a control signal for controlling a switching between an output permitted state and an output prohibited state is inputted; a first switching element provided between the first terminal and the second terminal and having a gate; a gate control circuit to which signals are inputted from the output control terminal and the second terminal, and which controls the first switching element to be conducting or to be non-conducting; and a second switching device provided between a power source of the second power supply voltage and the second terminal, and configured to switch between conducting and non-conducting in accordance with the electric potential of the second terminal, wherein the gate control circuit supplies the reference voltage to the gate of the first switching element, when the control signal corresponding to the output prohibited state is inputted to the output control terminal, the gate control circuit controls the first switching element to be conducting by supplying the gate of the first switching element with a second gate voltage higher than the reference voltage, when the control signal corresponding to the output permitted state is inputted to the output control terminal and the voltage of the second terminal is equal to the reference voltage, and the gate control circuit controls the first switching element to be non-conducting by supplying the gate of the first switching element with the lower one of the second gate voltage and the first power supply voltage, as a first gate voltage, when the control signal corresponding to the output permitted state is inputted to the output control terminal and the voltage of the second terminal is equal to the second power supply voltage.