Differential driver with common-mode voltage tracking and method

A method for maintaining a common-mode voltage in a transceiver circuit which provides an output differential signal during a transmission mode and receives an input differential signal during a receiving mode, comprising:

• providing a transmitter driver circuit which, in the transmission mode, drives the output differential signal, and wherein, in the receiving mode, provides a termination circuit for the input differential signal and provides a current that is provided in the transmission mode;
• and
• providing a first resistance between a supply voltage and the transmitter driver circuit during the transmission mode and providing a second resistance in the receiving mode, such that a common-mode voltage of the output differential signal substantially equals a common-mode voltage in the input differential signal at the termination circuit.

A transceiver that maintains a common-mode voltage between a transmission mode and a receiving mode, comprising:

• means for driving an output differential signal in the transmission mode, for providing a termination circuit for the input differential signal in the receiving mode, and for tracking in the receiving mode a current that is provided in the transmission mode;
• and
• means for providing a first resistance between a supply voltage and the transmitter driver circuit during the transmission mode and providing a second resistance in the receiving mode, such that a common-mode voltage of the output differential signal substantially equals a common-mode voltage in the input differential signal at the termination circuit.