Mode dependent driving of the center tap in ethernet communications

摘要

An output stage comprising a current mode line driver, a voltage mode line driver, and a center-tapped transformer for coupling data provided by the line drivers to a transmission line is provided herein. The output stage is configured to operate in a backwards compatible Ethernet communication device. For example, the Ethernet communication device is configured to support 10G Ethernet and legacy Ethernet modes of 10BASE-T, 100BASE-T, and 1000BASE-T. The current mode line driver can be utilized while operating in the 10G Ethernet mode to provide high linearity. The voltage mode line driver can be utilized while operating in legacy mode to conserve power. In order to accommodate the use of two different line drivers, a switch and/or a voltage regulator is used to couple/decouple a dc voltage to a center-tap of the transformer based on which of the two different line drivers is currently active.