US 2009/0267654 A1 · High-Speed Transmit Driver Switching Arrangement

Abstract

The invention relates to a line driver to drive a transmission line with a differentially balanced signal, with selectable signal amplitude, with output impedance matched to a characteristic impedance of the transmission line, and with reduced dissipation. The line driver includes a first driver subcircuit including a first and a second group of resistors. To drive an output node with a first signal sense, the first group of resistors is selectively coupled to a first bias voltage terminal and the second group to a second bias voltage terminal. To drive the first output node with a second signal sense, the first and second groups of resistors are both selectively coupled to the second bias voltage terminal. The line driver includes a second driver subcircuit. The second driver subcircuit includes a third and fourth group of resistors that are correspondingly switched.

Claims27

Dependent claims

A line driver comprising a first driver subcircuit, the first driver subcircuit comprising a first plurality of switchable resistance elements, the first plurality of switchable resistance elements grouped into a first and a second group of switchable resistance elements,

wherein each element in the first group is coupled to a first bias voltage terminal and each element in the second group is coupled to a second bias voltage terminal to drive an output node of the first driver subcircuit with a first signal sense and a first signal amplitude, and
wherein each element of the first and second groups is coupled to the second bias voltage terminal to drive the output node of the first driver subcircuit with a second signal sense and the first signal amplitude.

A line driver comprising:

a first driver subcircuit comprising a first plurality of switchable resistance elements, the first plurality of switchable resistance elements grouped into a first group and a second group of switchable resistance elements, wherein each element in the first and second groups is coupled to a first bias voltage terminal to drive an output node of the first driver subcircuit with a first signal sense and a full signal amplitude, and wherein each element in the first group is coupled to the first bias voltage terminal and each element in the second group is coupled to a second bias voltage terminal to drive the output node of the first driver subcircuit with the first signal sense and a reduced signal amplitude;
and
a second driver subcircuit comprising a second plurality of switchable resistance elements, wherein each element in the second plurality of switchable resistance elements is coupled to the second bias voltage terminal to drive an output node of the second driver subcircuit with the first signal sense and the full signal amplitude, and wherein each element in the second plurality of switchable resistance elements is coupled to the second bias voltage terminal to drive the output node of the second driver subcircuit with the first signal sense and the reduced signal amplitude.

Dependencies are inferred from the claim text.

High-Speed Transmit Driver Switching Arrangement

Life of this patent

High-Speed Transmit Driver Switching Arrangement

Life of this patent

Abstract

Claims27