Power efficient transmitter with a high voltage swing for sending high speed data along long backplanes

摘要

A power efficient transmitter with a high voltage swing for sending high speed data along long backplanes includes a current switching current mode logic (CML) type driver connected to a transmitter output (TXP, TXN) and a low-voltage differential signalling (LVDS) type driver connected to the transmitter output via a terminating load (Rt) at an LVDS node which would, in a standard configuration, determine common mode or receiver bias voltage. The LVDS type stage is switched (INP, INN) in synchronism with the CML type stage to establish at that circuit node a voltage that is substantially the same as that as the ac driven leg of the CML type driver would take up, thereby reducing current through the terminating load.