Feedforward Ethernet Line Driver for Low-Voltage Peak Swing

Solution Overview

Problem

Conventional Ethernet line drivers face inefficiencies and high power consumption due to their inability to operate effectively across multiple Ethernet modes using low voltage supplies, as they require different peak voltage swings and are either current or voltage mode based, leading to excess power consumption and inefficiency.

Innovation Solution

The development of low power network interface circuits with hybrid drivers that utilize a voltage mode first amplifier and a second amplifier with feedforward current output to selectively provide additional voltage swing, allowing operation with a 2.5V supply voltage for 10/100/1000Base-T Ethernet signals, while minimizing power consumption by disabling the feedforward current output for 1000Base-T or 100Base-T modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a voltage mode driver is used to support 10Base-Te mode with high peak voltage swing, then the voltage swing requirement is met, but the power consumption increases and a 3.6V supply is required

Engineering Contradiction:

Improvevoltage swing capabilityVSAvoidpower consumption

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The driver dynamically switches between voltage mode and current mode operation based on the Ethernet mode being used. For 10Base-Te mode requiring high voltage swing, the driver operates in voltage mode. For 100/1000Base-T modes with lower voltage requirements, it switches to current mode operation, thereby adapting its characteristics to match the specific operational requirements and minimizing power consumption in each mode

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The driver changes its operating parameters (voltage swing amplitude, current drive level) based on the detected Ethernet mode. It adjusts the peak voltage swing from the high levels needed for 10Base-Te to the lower levels sufficient for 100/1000Base-T, and相应ly adjusts the supply voltage requirement from 3.6V to 2.5V, optimizing power consumption for each specific mode

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If a current mode driver is used, then the driver can operate with lower voltage supply, but half the current is wasted in internal resistance leading to low efficiency

Engineering Contradiction:

Improvevoltage supply compatibilityVSAvoidcurrent waste

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The driver dynamically switches between voltage mode and current mode operation based on the Ethernet mode being used. For 10Base-Te mode requiring high voltage swing, the driver operates in voltage mode. For 100/1000Base-T modes with lower voltage requirements, it switches to current mode operation, thereby adapting its characteristics to match the specific operational requirements and minimizing power consumption in each mode

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The driver changes its operating parameters (voltage swing amplitude, current drive level) based on the detected Ethernet mode. It adjusts the peak voltage swing from the high levels needed for 10Base-Te to the lower levels sufficient for 100/1000Base-T, and相应ly adjusts the supply voltage requirement from 3.6V to 2.5V, optimizing power consumption for each specific mode

Inventive Principle:

Principle #35Parameter changes

3Strength

If a voltage mode driver operates at 3.6V supply to support 10Base-Te mode, then the peak voltage swing requirement is met, but excess power is consumed for 1000Base-T mode operation

Engineering Contradiction:

Improvepeak voltage swingVSAvoidexcess power consumption

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The driver dynamically switches between voltage mode and current mode operation based on the Ethernet mode being used. For 10Base-Te mode requiring high voltage swing, the driver operates in voltage mode. For 100/1000Base-T modes with lower voltage requirements, it switches to current mode operation, thereby adapting its characteristics to match the specific operational requirements and minimizing power consumption in each mode

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The driver changes its operating parameters (voltage swing amplitude, current drive level) based on the detected Ethernet mode. It adjusts the peak voltage swing from the high levels needed for 10Base-Te to the lower levels sufficient for 100/1000Base-T, and相应ly adjusts the supply voltage requirement from 3.6V to 2.5V, optimizing power consumption for each specific mode

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11283408B2Low voltage feedforward current assist ethernet line driver

Publication Date: 2022.03.22 TEXAS INSTRUMENTS INC

AI summary

Described examples include Ethernet physical layer (PHY) interface integrated circuits with transmit interface circuitry for transmitting data to an Ethernet network through a magnetic interface, which includes a voltage mode first amplifier with an output that generates a first voltage signal from a supply voltage according to a data input signal. The transmit interface circuit also includes a feedforward second amplifier circuit with an output stage that operates in a first mode to generate a current signal from the supply voltage according to the first voltage signal and to provide the current signal to the first amplifier output to boost a peak voltage at the output above the supply voltage to facilitate support for higher peak signal voltage swings for 10Base-T applications while using 2.5 volt or other low voltage supply levels.