US Patent 7248075 Level shifter with low leakage current

A voltage level shift circuit includes a first stage which receives an input signal having voltage levels Vcc and Vss, where Vcc>Vss, and which outputs complementary first and second intermediate signals, wherein the complementary first and second intermediate signals have voltage levels VIhigh and VIlow, where VIhigh>VIlow; and a second stage which receives the first and second intermediate signals, and which outputs complementary first and second output signals, wherein the complementary first and second output signals have voltage levels VOhigh and VOlow, where VOhigh>VOlow, wherein VIhigh>VOhigh or VIlow<VOlow, and wherein VOhigh>Vcc and VOlow<Vss.