Differential driver having multiple output voltage ranges

摘要

A differential driver includes an input stage and an output stage. The input stage receives a differential INPUT signal to produce a differential DRIVE signal of state determined by the INPUT signal. The output stage receives the DRIVE signal and produces a differential OUTPUT signal of state determined by the DRIVE signal. The OUTPUT signal voltage can be adjusted within any of multiple ranges. The output stage adjusts its output load resistance for each OUTPUT signal voltage range in order to maximize operating speed while limiting power consumption in each range. The input stage automatically reduces the voltage of the DRIVE signal input to the output stage for low OUTPUT signal voltages to reduce noise in the OUTPUT signal.