PoE Power Sourcing Equipment Data-Active Pair Enforcement

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Solution Overview

Problem

The lack of enforcement in Power over Ethernet (PoE) systems regarding the use of twisted wire pairs for power delivery can lead to improper operation or damage of powered devices (PDs) if power is injected through incorrect wire pairs, and may result in manufacturer-imposed restrictions.

Innovation Solution

Implementing electronic circuitry that enforces power delivery only through data-active pairs of data communications cabling, dynamically adjusting the wire pairs used based on data rate negotiations between Power Sourcing Equipment (PSE) and PDs, ensuring power is only delivered over pairs that actively carry data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If power is delivered over all twisted wire pairs without enforcement, then power delivery capability is maximized, but device reliability deteriorates due to improper power injection

Engineering Contradiction:
Improvepower delivery capabilityVSAvoiddevice reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies local quality by delivering power selectively over specific wire pairs that are actively carrying data, rather than uniformly over all wire pairs. The PSE identifies which wire pairs are data-active and restricts power delivery to only those pairs, ensuring that power is injected only where it is safe and appropriate for the connected device.

Inventive Principle:
Principle #3Local quality

2Reliability

If power delivery is restricted to data-active pairs only, then device safety is improved, but power delivery flexibility worsens

Engineering Contradiction:
Improvedevice safetyVSAvoidpower delivery flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamics by making power delivery adaptive to changing data transmission conditions. As data rates and wire pair usage change dynamically during operation, the PSE continuously monitors which wire pairs are data-active and adjusts power delivery accordingly. This allows the system to adapt to different scenarios (100 Mbps, 1 Gbps, full-duplex modes) while maintaining safety.

Inventive Principle:
Principle #15Dynamics

3Reliability

If enforcement circuitry is added to monitor data-active pairs, then power delivery safety is improved, but system complexity increases

Engineering Contradiction:
Improvepower delivery safetyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the PSE to perform multiple functions: it simultaneously manages data transmission, monitors wire pair activity, negotiates power requirements, and controls power delivery. By integrating these functions into a single multi-functional device, the patent avoids adding separate dedicated enforcement hardware, thereby limiting the increase in system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS8185764B2Techniques for ensuring power delivery over only data-active pairs of data communications cabling
Publication Date: 2012.05.22 CISCO TECHNOLOGY INC

AI summary

A power delivery technique which involves connecting power sourcing equipment (PSE) with a powered device (PD) through data communications cabling (e.g., an Ethernet cable). The technique further involves negotiating an acceptable power level for the PD and a data rate for the PD, and enforcing delivery of power to the PD using only wire pairs of the data communications cabling which carry data between the PSE and the PD. As a result, the PSE does not deliver any power to the PD through wire pairs which are not data-active.