IP Library › Granted Patent US 12706568
Granted Patent B2
US 12706568 · App. 17/972,532 · Granted Aug 11, 2026

Dual-mode line driver for ethernet applications

Inventors: Srikanth Manian (Bangalore, IN); Sumantra Seth (Bangalore, IN); Trilok Kamagond (Bangalore, IN)
Assignee: TEXAS INSTRUMENTS INCORPORATED
H03F1/02H03F3/45475H03F2200/129H03F2200/91H03F2203/45526H03F2203/45528H03F2203/45534
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Quick Facts
Patent No.
US 12706568
App. No.
17/972,532
Granted
Aug 11, 2026
Kind
B2
Abstract

A driver includes an operational amplifier which includes a first amplifier input coupled to a first driver input, a second amplifier input coupled to a second driver input, a first amplifier output, a second amplifier output, a third amplifier output and a fourth amplifier output. The first amplifier output is coupled to the first driver output and the third amplifier output is coupled to the second driver output in a voltage-mode operation. The second amplifier output is coupled to the first driver output and the fourth amplifier output is coupled to the second driver output in a current-mode operation.

Claims (115)

1 . A driver comprising:

a first driver input;

a second driver input;

a first driver output;

a second driver output;

an operational amplifier comprising:

a first amplifier input coupled to the first driver input;

a second amplifier input coupled to the second driver input;

a first amplifier output;

a second amplifier output;

a third amplifier output;

a fourth amplifier output, wherein output current supplied by the second amplifier output and the fourth amplifier output is greater than output current supplied by the first amplifier output and the third amplifier output;

a first resistor;

a first switch to selectively couple the first amplifier output to the first driver output via the first resistor;

a second resistor;

a second switch to selectively couple the first amplifier output to the first driver output via the second resistor;

a third resistor;

a third switch to selectively couple the third amplifier output to the second driver output via the third resistor;

a fourth resistor;

a fourth switch to selectively couple the third amplifier output to the second driver output via the fourth resistor;

a fifth resistor;

a fifth switch to selectively couple the first amplifier output to the third amplifier output via the fifth resistor;

a sixth switch to selectively couple the second amplifier output to the first driver output; and

a seventh switch to selectively couple the fourth amplifier output to the second driver output.

2 . The driver of claim 1 , wherein the first and the third resistor have equal resistance values.

3 . The driver of claim 1 , wherein the second and the fourth resistor have equal resistance values.

4 . The driver of claim 1 , wherein the first switch is closed in a voltage-mode operation to couple the first amplifier output to the first driver output, and wherein the second switch is closed in a current-mode operation to couple the first amplifier output to the first driver output.

5 . The driver of claim 1 , wherein the third switch is closed in a voltage mode operation to couple the third amplifier output to the second driver output, and wherein the fourth switch is closed in a current-mode operation to couple the third amplifier output to the second driver output.

6 . The driver of claim 1 , wherein the fifth switch is closed in a current-mode operation to couple the fifth resistor across the first and the third amplifier outputs.

7 . The driver of claim 1 , wherein the sixth switch is closed in a current mode operation to couple the second amplifier output to the first driver output, and wherein the seventh switch is closed in the current mode operation to couple the fourth amplifier output to the second driver output.

8 . A driver comprising:

a first driver input;

a second driver input;

a first driver output;

a second driver output; and

an operational amplifier comprising:

a first amplifier input coupled to the first driver input;

a second amplifier input coupled to the second driver input;

a first voltage-mode amplifier output coupled to the first driver output via a first resistor in a voltage-mode operation and coupled to the first driver output via a second resistor in a current-mode operation;

a first current-mode amplifier output coupled to the first driver output in the current-mode operation;

a second voltage-mode amplifier output coupled to the second driver output via a third resistor in the voltage-mode operation and coupled to the second driver output via a fourth resistor in the current-mode operation; and

a second current-mode amplifier output coupled to the second driver output in the current-mode operation, wherein output current supplied by the first current-mode amplifier output and the second current-mode amplifier output is greater than output current supplied by the first voltage-mode amplifier output and the second voltage-mode amplifier output.

9 . The driver of claim 8 further comprising a fifth resistor coupled between the first and second voltage-mode amplifier outputs in the current-mode operation.

10 . The driver of claim 8 , wherein the first and the third resistor have equal resistance values.

11 . The driver of claim 8 , wherein the second and the fourth resistor have equal resistance values.

12 . A system comprising:

a digital signal processor (DSP) including an output;

a digital-to-analog converter (DAC) including an input coupled to the output of the DSP and including first and second outputs; and

a driver comprising:

a first driver input adapted to be coupled to the first output of the DSP;

a second driver input adapted to be coupled to the second output of the DSP;

a first driver output;

a second driver output;

an operational amplifier comprising:

a first amplifier input coupled to the first driver input;

a second amplifier input coupled to the second driver input;

a first amplifier output;

a second amplifier output;

a third amplifier output; and

a fourth amplifier output, wherein output current supplied by the second amplifier output and the fourth amplifier output is greater than output current supplied by the first amplifier output and the third amplifier output;

a first resistor;

a first switch to selectively couple the first amplifier output to the first driver output via the first resistor;

a second resistor;

a second switch to selectively couple the first amplifier output to the first driver output via the second resistor;

a third resistor;

a third switch to selectively couple the third amplifier output to the second driver output via the third resistor;

a fourth resistor;

a fourth switch to selectively couple the third amplifier output to the second driver output via the fourth resistor;

a fifth resistor;

a fifth switch to selectively couple the first amplifier output to the third amplifier output via the fifth resistor;

a sixth switch to selectively couple the second amplifier output to the first driver output; and

a seventh switch to selectively couple the fourth amplifier output to the second driver output.

13 . The system of claim 12 , wherein the first and the third resistor have equal resistance values and the second and the fourth resistor have equal resistance values.

14 . A system comprising:

a digital signal processor (DSP) including an output;

a digital-to-analog converter (DAC) including an input coupled to the output of the DSP and including first and second outputs; and

a dual-mode driver configured for a voltage-mode operation and a current-mode operation, the driver comprising:

a first driver input;

a second driver input;

a first driver output;

a second driver output;

an operational amplifier comprising:

a first amplifier input coupled to the first driver input;

a second amplifier input coupled to the second driver input;

a first voltage-mode amplifier output coupled to the first driver output via a first resistor in the voltage-mode operation and coupled to the first driver output via the first resistor in the current-mode operation, wherein the first resistor has a first resistance value in the voltage-mode operation and has a second resistance value in the current-mode operation;

a first current-mode amplifier output coupled to the first driver output in the current-mode operation;

a second voltage-mode amplifier output coupled to the second driver output via a second resistor in the voltage-mode operation and coupled to the second driver output via the second resistor in the current-mode operation, wherein the second resistor has the first resistance value in the voltage-mode operation and has the second resistance value in the current-mode operation; and

a second current-mode amplifier output coupled to the second driver output in the current-mode operation, wherein output current supplied by the first current-mode amplifier output and the second current-mode amplifier output is greater than output current supplied by the first voltage-mode amplifier output and the second voltage-mode amplifier output.

15 . The system of claim 14 , further comprising a third resistor coupled between the first and second voltage-mode amplifier outputs in the current-mode operation.

16 . The driver of claim 1 , wherein:

the first switch includes a first terminal coupled to the first amplifier output;

the first resistor includes a first terminal coupled to a second terminal of the first switch and a second terminal coupled to the first driver output;

the second switch includes a first terminal coupled to the first amplifier output;

the second resistor includes a first terminal coupled to a second terminal of the second switch and a second terminal coupled to the first driver output;

the third switch includes a first terminal coupled to the third amplifier output;

the third resistor includes a first terminal coupled to a second terminal of the third switch and a second terminal coupled to the second driver output;

the fourth switch includes a first terminal coupled to the third amplifier output;

the fourth resistor includes a first terminal coupled to a second terminal of the fourth switch and a second terminal coupled to the second driver output;

the fifth switch includes a first terminal coupled to the first amplifier output;

the fifth resistor including a first terminal coupled to a second terminal of the fifth switch and a second terminal coupled to the third amplifier output;

the sixth switch includes a first terminal coupled to the second amplifier output and a second terminal coupled to the first driver output; and

the seventh switch including a first terminal coupled to the fourth amplifier output and a second terminal coupled to the second driver output.

17 . The system of claim 12 , wherein:

the first switch includes a first terminal coupled to the first amplifier output;

the first resistor includes a first terminal coupled to a second terminal of the first switch and a second terminal coupled to the first driver output;

the second switch includes a first terminal coupled to the first amplifier output;

the second resistor includes a first terminal coupled to a second terminal of the second switch and a second terminal coupled to the first driver output;

the third switch includes a first terminal coupled to the third amplifier output;

the third resistor includes a first terminal coupled to a second terminal of the third switch and a second terminal coupled to the second driver output;

the fourth switch includes a first terminal coupled to the third amplifier output;

the fourth resistor includes a first terminal coupled to a second terminal of the fourth switch and a second terminal coupled to the second driver output;

the fifth switch includes a first terminal coupled to the first amplifier output;

the fifth resistor including a first terminal coupled to a second terminal of the fifth switch and a second terminal coupled to the third amplifier output;

the sixth switch includes a first terminal coupled to the second amplifier output and a second terminal coupled to the first driver output; and

the seventh switch including a first terminal coupled to the fourth amplifier output and a second terminal coupled to the second driver output.