Line Driver Method and Apparatus

• US 20090237122A1
• Filed: 03/19/2008
• Published: 09/24/2009
• Est. Priority Date: 03/19/2008
• Status: Active Grant

• Current Assignee: Intel Germany GmbH (Intel Corporation)
• Original Assignee: Infineon Technologies AG
• Inventors: Traber, Mario, Wenske, Holger, Eichler, Thomas
• Granted Patent: US 8,896,351 B2
• Time in Patent Office: Days
• US Class Current: 327/108
• CPC Class Codes: H04L 25/0264 Arrangements for coupling to transmission lines duplexing arrangements H04L5/14; line equalisers, line build-out devices H04L25/03878

Abstract

According to one embodiment, a line driver circuit comprises a plurality of output stages each operable to produce an output signal and one or more pre-output stages operable to perform one or more common functions. The line driver circuit also comprises circuitry operable to selectively couple one or more of the output stages to the one or more pre-output stages based on a wireline communication technology implemented by the line driver circuit.

Claims

1. A line driver circuit, comprising:

a plurality of output stages each operable to produce an output signal;

one or more pre-output stages operable to perform one or more common functions; and

circuitry operable to selectively couple one or more of the output stages to the one or more pre-output stages based on a wireline communication technology implemented by the line driver circuit.

2. The line driver circuit of claim 1, wherein the circuitry is operable to selectively decouple at least one of the output stages not coupled to the one or more pre-output stages.

3. The line driver circuit of claim 1, wherein the circuitry comprises:

a first group of switches operable to selectively couple and decouple different ones of the output stages to the one or more pre-output stages based on the wireline communication technology implemented by the line driver circuit; and

a second group of switches operable to deactivate each output stage decoupled from the one or more pre-output stages.

4. The line driver circuit of claim 1, wherein each output stage comprises an amplifier and feedback and feed-forward impedances selectively coupled between the amplifier and the one or more pre-output stages.

5. The line driver circuit of claim 1, wherein the one or more pre-output stages comprise biasing circuitry operable to bias each output stage coupled to the one or more pre-output stages.

6. The line driver circuit of claim 5, wherein the amount of bias provided by the biasing circuitry is programmable based on the number and performance requirements of output stages coupled to the one or more pre-output stages.

7. The line driver circuit of claim 1, wherein the circuitry is operable to couple one or more of the output stages to the one or more pre-output stages and decouple remaining ones of the output stages from the one or more pre-output stages based on hardwired information provided to the line driver circuit.

8. The line driver circuit of claim 1, wherein the circuitry is operable to change a coupling configuration of the output stages with the one or more pre-output stages responsive to a change in the wireline communication technology implemented by the line driver circuit.

9. The line driver circuit of claim 1, wherein the circuitry is operable to select the one or more output stages operable to produce an output signal which satisfies voltage and current conditions associated with the wireline communication technology implemented by the line driver circuit.

10. The line driver circuit of claim 1, wherein the plurality of output stages are operable to meet signal requirements for at least two different ones of 10BASE-T Ethernet, 100BASE-T Ethernet, Gigabit Ethernet, 10 Gigabit Ethernet and 100 Gigabit Ethernet when coupled to the one or more pre-output stages.

11. The line driver circuit of claim 1, wherein one or more of the output stages are operable to meet signal requirements for a xDSL technology when coupled to the one or more pre-output stages and wherein one or more different ones of the output stages are operable to meet signal requirements for an E-carrier technology or T-carrier technology when coupled to the one or more pre-output stages.

12. The line driver circuit of claim 1, wherein at least one of the output stages comprises:

a voltage-mode line driver having an input, an output and an output impedance;

a feedback impedance coupled between the output and the input of the voltage-mode line driver;

a feed-forward impedance coupled between the input and the output of the voltage-mode line driver;

a termination impedance coupled between the output of the voltage-mode line driver and a transmission line and operable to sense current and voltage output by the voltage-mode line driver;

wherein the output impedance of the voltage-mode line driver is synthesized based on the feedback and feed-forward impedances;

wherein a total output impedance of the output stage corresponds to the output impedance of the voltage-mode line driver and the termination impedance and approximately matches an impedance of the transmission line; and

wherein the magnitude of the termination impedance corresponds approximately to the difference between the transmission line impedance and the output impedance of the voltage-mode line driver.

13. A method, comprising:

providing one or more pre-output stages and a plurality of output stages, each output stage being operable to produce an output response corresponding to a wireline communication technology when coupled to the one or more pre-output stages, the one or more pre-output stages being operable to perform one or more functions common to the plurality of output stages;

selectively coupling one or more of the output stages to the one or more pre-output stages based on the wireline communication technology; and

decoupling remaining ones of the output stages from the one or more pre-output stages.

14. The method of claim 13, wherein coupling one or more of the output stages to the one or more pre-output stages comprises selectively coupling one or more inverting amplifiers to the one or more pre-output stages based on the wireline communication technology.

15. The method of claim 14, wherein decoupling remaining ones of the output stages from the one or more pre-output stages comprises applying a ground potential to an n-FET transistor and a voltage potential to a p-FET transistor included in each inverting amplifier decoupled from the one or more pre-output stages.

16. The method of claim 13, further comprising programming an amount of bias provided to each output stage coupled to the one or more pre-output stages based on the number of output stages coupled to the one or more pre-output stages.

17. The method of claim 13, further comprising changing a coupling configuration of the output stages with the one or more pre-output stages responsive to a different wireline communication technology.

18. The method of claim 17, wherein changing the coupling configuration of the output stages with the one or more pre-output stages comprises changing the coupling configuration responsive to the wireline communication technology being changed from one Ethernet technology to another Ethernet technology.

19. The method of claim 17, wherein changing the coupling configuration of the output stages with the one or more pre-output stages comprises changing the coupling configuration responsive to the wireline communication technology being changed from digital subscriber loop technology to E-carrier technology or T-carrier technology or from the E-carrier technology or the T-carrier technology to the digital subscriber loop technology.

20. A line driver circuit, comprising:

a plurality of output stages each operable to produce an output signal;

one or more pre-output stages operable to perform one or more common functions; and

means for selectively coupling one or more of the output stages to the one or more pre-output stages based on a wireline communication technology implemented by the line driver circuit.

21. An Ethernet line driver circuit, comprising:

a voltage-mode line driver having an input, an output and an output impedance;

a transformer having a primary winding coupled to the output of the voltage-mode line driver and a secondary winding operable to drive a transmission line;

a feedback impedance coupled between the output and the input of the voltage-mode line driver;

a feed-forward impedance coupled between the input of the voltage-mode line driver and the primary winding of the transformer;

a termination impedance coupled to the primary winding of the transformer and operable to sense current and voltage output by the voltage-mode line driver;

wherein the output impedance of the voltage-mode line driver is synthesized based on the feedback and feed-forward impedances;

wherein a total output impedance of the Ethernet line driver circuit corresponds to the output impedance of the voltage-mode line driver and the termination impedance and approximately matches an impedance of the transmission line; and

wherein the magnitude of the termination impedance corresponds approximately to the magnitude of the difference between the transmission line impedance and the output impedance of the voltage-mode line driver.

22. The Ethernet line driver circuit of claim 21, wherein the termination impedance is coupled between the feedback impedance and the primary winding of the transformer.

23. The Ethernet line driver circuit of claim 22, wherein the termination impedance comprises a first element coupled between a first element of the feedback impedance and a first input terminal of the primary winding and a second element coupled between a second element of the feedback impedance and a second input terminal of the primary winding.

24. The Ethernet line driver circuit of claim 21, wherein the termination impedance is coupled between the feed-forward impedance and the primary winding of the transformer.

25. The Ethernet line driver circuit of claim 24, wherein a first element of the feedback impedance is coupled between a first input terminal of the primary winding and a first input impedance element, a second element of the feedback impedance is coupled between a second input terminal of the primary winding and a second input impedance element, the termination impedance is coupled between first and second tap points of the primary winding, a first element of the feed-forward impedance is coupled between the first tap point and the first input impedance element, and a second element of the feed-forward impedance is coupled between the second tap point and the second input impedance element.