USB Repeater Hysteresis Circuit for End-of-Packet Dribble Rejection

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Solution Overview

Problem

Conventional USB repeaters experience end-of-packet dribble due to noise amplification during high-speed communications, leading to spurious signal levels that can cause data corruption or link failure, without effective solutions that do not increase die area or power consumption.

Innovation Solution

Implementing a USB repeater with a hysteresis stage in the receiver circuit to offset differential signals, reducing EOP dribble by applying an opposing current to the hysteresis stage, independent of equalization settings and without additional trim bits or increased power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional USB repeaters amplify differential signals during high-speed communications, then signal transmission is achieved, but noise amplification occurs causing end-of-packet dribble and data corruption

Engineering Contradiction:

Improvedata integrityVSAvoidEOP dribble

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing a hysteresis stage that generates an opposing offset current before the noise amplification can occur. This offset current counteracts the differential signal during the end-of-packet period, preventing the harmful EOP dribble from being amplified in the first place, thereby maintaining data integrity without sacrificing signal transmission reliability

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If a hysteresis stage with offset current is added to reduce EOP dribble, then data integrity improves, but die area and power consumption increase

Engineering Contradiction:

Improvedata integrityVSAvoiddie area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the hysteresis stage with the existing receiver circuitry by integrating the offset current generation within the differential amplifier structure. The hysteresis feedback is combined with the signal amplification path, allowing the same circuit elements to perform both signal processing and EOP dribble suppression functions, thereby minimizing additional die area

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The hysteresis stage is designed to serve multiple functions: it provides noise immunity during signal reception, generates the offset current to suppress EOP dribble, and maintains compatibility with existing equalization settings. This multi-functionality reduces the need for separate dedicated circuits, minimizing the increase in die area

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a hysteresis stage with offset current is added to reduce EOP dribble, then data integrity improves, but power consumption increases

Engineering Contradiction:

Improvedata integrityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges the hysteresis stage with the existing receiver circuitry, allowing the offset current to be generated using the same power supply and circuit elements already present in the differential amplifier. This integration ensures that the additional power consumption is minimal and shared with the existing signal processing functions

Inventive Principle:

Principle #5Merging (Combining)

4Speed

If conventional repeaters transmit amplified signals, then communication speed is maintained, but spurious signal levels cause link failure

Engineering Contradiction:

Improvecommunication speedVSAvoidlink stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The hysteresis stage applies preliminary anti-action by generating an offset current that counteracts spurious signal levels before they can cause link failure. This offset is particularly effective during the end-of-packet period when noise is most problematic, allowing high-speed communication to continue without compromising link stability

Inventive Principle:

Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Reduces EOP dribble effectively, preventing data corruption and link failure in high-speed USB communications, while maintaining scalability and avoiding increased die area or power consumption.

Implementation Method 1

An offset is applied to a hysteresis stage in the receiver that is coupled to the first and second output nodes

Methodology Applied

Scientific EffectHysteresis: Hysteresis

Data Source

PatentUS20250330212A1Rejection of end-of-packet dribble in high speed universal serial bus repeaters

Publication Date: 2025.10.23 TEXAS INSTRUMENTS INC

AI summary

Universal Serial Bus (USB) repeater circuits and methods of operating the same for communicating data signals from a first pair of data terminals to a second pair of data terminals of the repeater. In a first channel, an amplifier stage in a receiver amplifies a differential signal received at the first pair of data terminals to generate a differential signal at first and second output nodes of the receiver, and a transmitting circuit transmits a differential signal at the second pair of data terminals responsive to the differential signal at the first and second output nodes of the receiver. The receiver includes a hysteresis stage that receives an offset in opposition to the differential signal at the first and second output nodes of the receiver. End-of-packet (EOP) dribble in USB communications in the HS mode is reduced by the offset at the hysteresis stage.