Patent ID: 7161386

Claim:
A signal-level converter provided between a first terminal and a second terminal, for two-way signal transfer between the terminals, the first terminal being connected to a first logic circuit operating at a first supply voltage higher than a given reference voltage, the second terminal being connected to a second logic circuit operating at a second supply voltage higher than the first supply voltage, the signal-level converter comprising: a switching transistor that forms a current passage between the first and the second terminals in response to a control signal supplied to a gate of the switching transistor; a first bus-hold circuit, provided between the switching transistor and the second terminal, and configured to convert a voltage level of a signal transferred via the switching transistor into another voltage level at the second terminal when the first terminal is an input terminal whereas the second terminal is an output terminal, the first bus-hold circuit being capable of connecting the second terminal to the second supply voltage and a reference voltage; and a second bus-hold circuit, provided between the switching transistor and the first terminal, and configured to convert a voltage level of a signal transferred via the switching transistor into another voltage level at the first terminal when the second terminal is an input terminal whereas the first terminal is an output terminal, the second bus-hold circuit being capable of connecting the first terminal to the first supply voltage and a reference voltage.