Level-shift circuits and related methods

摘要

A level shift circuit and method for level shifting the common-mode voltage of a power-supply-referenced circuit to the common-mode voltage of a ground-referenced circuit. The level shift circuit and method entails performing a common-mode level shifting of input complementary signals derived from the power-supply-referenced circuit to produce output complementary signals for the ground-referenced circuit. Because the level shifting is performed in a common manner (i.e. the level shift or voltage drop is common to both complementary signals), pulse-width distortion is substantially reduced if not eliminated. The level shift circuit includes a voltage drop device common to both sides of a differential pair to produce the desired level shift of the output complementary signals. Yet another embodiment relates to a multi-stage level shift circuit and method for level shifting in steps an input common-mode voltage to an output common-mode voltage.