US Patent 7342417 Low-leakage level shifter with integrated firewall and method

A level shifter may reduce leakage current and provide firewall protection between circuits of different voltage domains when one voltage domain is in a standby mode. The level shifter may either couple or decouple input circuitry from a reference voltage in response to a firewall enable signal, may translate signals between a first voltage domain and a second voltage domain when the firewall enable signal is deasserted, and may generate an output signal having a predetermined one of either a high or low state when the firewall enable signal is asserted.