Energy efficient line-driver with improved output swing
In some aspects, the disclosure is directed to methods and systems for one or more line-drivers configured to selectively operate between a plurality of modes. When operating as a voltage-mode line-driver increased power efficiency may be realized. When operating as a current-mode line-driver, an increased transmission power may be realized. When operating in a dual/additive mode, still further increased transmission power may be realized.
1 . A device comprising:
an interface configured to communicate over a protocol having a plurality of output levels;
a first transceiver output configured for proximal connection in series with a near-end termination circuit of a first transmission line;
a second transceiver output configured for distal connection with the near-end termination circuit;
a first select line, configured to enable the first transceiver output; and a second select line, configured to enable the second transceiver output, wherein:
in a first mode of operation:
the first transceiver output is enabled;
the second transceiver output is disabled; and
the interface communicates at a first output level of the plurality of output levels, and
in a second mode of operation:
the second transceiver output is enabled; the first transceiver output is disabled; and
the interface communicates at a second output level of the plurality of output levels.
2 . The device of claim 1 , wherein:
the first transceiver output and the second transceiver output are selectable outputs from a same transceiver;
the transceiver comprises:
first and second positive output terminals; and
first and second negative output terminals;
the first and second positive output terminals are intermediated by a first termination resistor of the near-end termination circuit; and
the first and second negative output terminals are intermediated by a second termination resistor.
3 . The device of claim 1 , comprising a third select line to cause the second transceiver output to enter a low impedance state.
4 . The device of claim 1 , wherein the interface is configured to adjust the first select line and the second select line responsive to a type of the protocol.
5 . The device of claim 1 , wherein the interface is configured to adjust the first select line and the second select line responsive to a symbol received for transmission.
6 . The device of claim 1 , wherein in a third mode of operation, the first transceiver output and the second transceiver output are enabled.
7 . The device of claim 1 , wherein the near-end termination circuit comprises:
first inputs configured to receive first differential signals; and
second inputs, different from the first inputs, configured to transmit second differential signals.
8 . A circuit comprising:
a first select line, configured to enable a first transceiver output in series with a near-end termination circuit of a first transmission line to cause the circuit to generate output signals at a first output level of a plurality of output levels;
a second select line, configured to enable a second transceiver output configured for distal connection with the near-end termination circuit to cause the circuit to generate output signals at a second output level of the plurality of output levels; and
a selection circuit to select one or more of the first select line and the second select line.
9 . The circuit of claim 8 , wherein the selection circuit is configured to simultaneously select the first select line and the second select line.
10 . The circuit of claim 8 , wherein:
the first transceiver output and the second transceiver output are selectable outputs from a same transceiver;
the transceiver comprises:
first and second positive output terminals; and
first and second negative output terminals;
the first and second positive output terminals are intermediated by a first termination resistor of the near-end termination circuit; and
the first and second negative output terminals are intermediated by a second termination resistor.
11 . The circuit of claim 8 , comprising a third select line to cause the second transceiver output to enter a low impedance state.
12 . The circuit of claim 8 , wherein the circuit is configured to adjust the first select line and the second select line responsive to a selected protocol.
13 . The circuit of claim 8 , wherein the circuit is configured to adjust the first select line and the second select line responsive to a symbol received for transmission.
14 . The circuit of claim 8 , wherein in a third mode of operation, the first transceiver output and the second transceiver output are enabled.
15 . The circuit of claim 8 , wherein the near-end termination circuit comprises:
first inputs configured to receive first differential signals; and
second inputs, different from the first inputs, configured to transmit second differential signals.
16 . A system comprising:
an interface configured to communicate over a protocol having a plurality of output levels;
a first transceiver output configured for proximal connection in series with a near-end termination circuit of a first transmission line;
a second transceiver output configured for distal connection with the near-end termination circuit;
a first select line, configured to enable the first transceiver output;
a second select line, configured to enable the second transceiver output; and
a third select line, configured to cause the second transceiver output to enter a low impedance state.
17 . The system of claim 16 , wherein:
in a first mode of operation, the first transceiver output is enabled, the second transceiver output is disabled, and the interface communicates at a first output level of the plurality of output levels, and
in a second mode of operation, the second transceiver output is enabled, the first transceiver output is disabled, and the interface communicates at a second output level of the plurality of output levels.
18 . The system of claim 17 , wherein in a third mode of operation, the first transceiver output and the second transceiver output are enabled.
19 . The system of claim 16 , wherein:
the first transceiver output and the second transceiver output are selectable outputs from a same transceiver;
the transceiver comprises:
first and second positive output terminals; and
first and second negative output terminals;
the first and second positive output terminals are intermediated by a first termination resistor of the near-end termination circuit; and
the first and second negative output terminals are intermediated by a second termination resistor.
20 . The system of claim 16 , wherein the interface is configured to adjust the first select line and the second select line responsive to a type of the protocol or responsive to a symbol received for transmission.