US Patent 7203243 Line driver with reduced power consumption

A means for reducing the power consumption of the transmitter by storing the recent history of the transmitted data using a string of gates with taps from the string taken at points determined by the propagation delay of each gate and controlling driving transistors as a function of comparison of that history with input data so that, either the signal is driven into the transmission line at full strength, or at a level near the minimum needed to retain the state in the receiver.