High-speed transmit driver switching arrangement

A line driver comprising:

• a first driver subcircuit comprising a first output configured to be coupled to a first terminal of a load, and 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;
• and
• a second driver subcircuit comprising a second output configured to be coupled to a second terminal of the load, and a second plurality of switchable resistance elements, wherein,
• in a first full amplitude configuration, each switchable resistance element in the first and second groups is coupled to a first bias voltage terminal and not coupled to a second bias voltage terminal, and each switchable resistance element in the second plurality of switchable resistance elements is coupled to the second bias voltage terminal and not coupled to the first voltage terminal to drive the load with a first signal sense and a full signal amplitude, the full signal amplitude being 100% of a full output voltage drive strength, and
• in a first reduced amplitude configuration, each switchable resistance element in the first group is coupled to the first bias voltage terminal and not coupled to the second voltage terminal, each switchable resistance element in the second group is coupled to the second bias voltage terminal and not coupled to the first voltage terminal, and each switchable resistance element in the second plurality of switchable resistance elements is coupled to the second bias voltage terminal and not coupled to the first voltage terminal to drive the load with the first signal sense and a reduced signal amplitude, the reduced signal amplitude being less than 100% of the full signal output voltage drive strength.

A method of producing an output signal of a line driver having a first output terminal configured to be coupled to a first terminal of a load, a first group of switchable resistance elements that are switchably coupled between a first output terminal of the line driver and either a first bias voltage terminal and not a second bias voltage terminal or the second bias voltage terminal and not the first bias voltage terminal and a second group of switchable resistance elements that are switchably coupled between the first output terminal and either the first bias voltage terminal and not the second bias voltage terminal or the second bias voltage terminal and not the first bias voltage terminal, the method comprising:

• driving the load with a first signal sense and a partial drive strength, driving the load with the first signal sense and the partial drive strength comprising coupling each resistance element of the first group to the first bias voltage terminal and not the second bias voltage terminal and coupling each resistance element of the second group to the second bias voltage terminal and not the first voltage terminal, wherein the partial drive strength comprises a drive strength less than 100% of a full drive strength;
• and
• driving the load with a second signal sense, driving the load with the second signal sense and the partial drive strength comprising coupling each resistance element of both the first and second groups to the second bias voltage terminal and not the first voltage terminal, wherein the second signal sense is opposite the first signal sense.

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, in a first partial drive strength configuration, each switchable resistance 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 partial drive strength the partial drive strength being less than 100% of a full output voltage drive strength;
• wherein, in a second partial drive strength configuration, each switchable resistance 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 partial drive strength, the second signal sense opposite the first signal sense;
• wherein, in a first full drive strength configuration, each switchable resistance element in the first and second groups is coupled to the first bias voltage terminal to drive the output node of the first driver subcircuit with the first signal sense and a full drive strength, the full drive strength being 100% of the full output voltage drive strength;
• and
• wherein, in a second full drive strength configuration, each switchable resistance 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 the second signal sense and the full drive strength.

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;

• and
• second driver subcircuit, the second driver subcircuit comprising a second plurality of switchable resistance elements, the second plurality of switchable resistance elements grouped into a third group and a fourth group of switchable resistance elements
• wherein, in a first partial drive strength configuration, each switchable resistance 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 partial drive strength, the partial drive strength being less than 100% of a full output voltage drive strength;
• wherein, in a second partial drive strength configuration, each switchable resistance 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 partial drive strength, the second signal sense opposite the first signal sense;
• wherein, in the first partial drive strength configuration, each element in the third and fourth groups 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 partial drive strength;
• and
• wherein, in the second partial drive strength configuration, each element in the third group is coupled to the first bias voltage terminal and each element in the fourth group is coupled to the second bias voltage terminal to drive the output node of the second driver subcircuit with the second signal sense and the partial drive strength;
• wherein, in a first full drive strength configuration, each switchable resistance element in the third and fourth groups is coupled to the second bias voltage terminal to drive the output node of the second driver subcircuit with the first signal sense and a full drive strength, the full drive strength being 100% of the full output voltage drive strength;
• and
• wherein, in second full drive strength configuration, each switchable resistance element in the third and fourth groups is coupled to the first bias voltage terminal to drive the output node of the second driver subcircuit with the second signal sense and the full drive strength.

A method of driving a load having a first terminal and a second terminal, the method comprising:

• driving the load with a partial amplitude and a first signal sense, the partial amplitude less than 100% of a full amplitude, driving the load with the first amplitude and the first signal sense comprising
• coupling a first group of resistors between the first terminal and a first bias voltage terminal,
• coupling a second group of resistors between the first terminal and a second bias voltage terminal,
• coupling a third group of resistors between the second terminal and the second bias voltage terminal, and
• coupling a fourth group of resistors between the second terminal and the second bias voltage terminal;
• and
• driving the load with the partial amplitude and a second signal sense, the second signal sense opposite the first signal sense, driving the load with the partial amplitude and a second signal sense comprising
• coupling the first group of resistors between the first terminal and the second bias voltage terminal,
• coupling the second group of resistors between the first terminal and a second bias voltage terminal,
• coupling the third group of resistors between the first terminal and the second bias voltage terminal, and
• coupling the fourth group of resistors between the second terminal and the second bias voltage terminal.