PoE Detection Circuit Interface Classification via Variable Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Power over Ethernet (PoE) systems do not provide a method to determine whether a powered device (PD) presents a single interface or two independent interfaces when receiving power over four twisted wire pairs, leading to inefficiencies in power distribution and classification.
Innovation Solution
A PoE connection check method that generates different detection power levels over two sets of wires to determine the number of interfaces by comparing power attribute indications, allowing the control circuitry to decide which power enable circuits to activate for power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If power is supplied over 4 twisted wire pairs without interface detection, then power distribution is simplified, but power efficiency and classification accuracy deteriorate
Solution Approach 1:
The system performs preliminary detection by applying detection voltages and measuring signature resistance values before activating full power distribution. This preliminary action identifies whether a single PD or multiple PDs are connected, enabling optimized power allocation without trial-and-error adjustments during operation.
Solution Approach 2:
The system uses feedback from measured signature resistance values to determine the number of active PD interfaces. Based on this feedback, the PSE adjusts power distribution strategy - applying full power when a single PD is detected or distributing power across multiple pairs when multiple PDs are detected, thereby optimizing power efficiency.
2Measurement precision
If detection power levels are increased to improve interface identification accuracy, then measurement precision improves, but energy consumption increases
Solution Approach 1:
The system applies detection voltages that are sufficient to obtain accurate signature resistance measurements but are lower than full operating power levels. By using partial action (detection voltages rather than full power), the system achieves adequate measurement precision while minimizing energy consumption during the detection phase.
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
Enables accurate determination of the number of PD interfaces, optimizing power distribution and classification, ensuring that power is provided efficiently and effectively to the PD.
Implementation Method 1
detection power source arranged to generate detection power at different voltage or current levels
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A power over Ethernet (PoE) connection check method comprising: for a first time period, generating a first detection power over the first set of wires while not generating a second detection power over the second set of wires (1000) and obtaining a first indication of a power attribute over the first set of wires (1010); during a second time period, generating the first detection power and generating a second detection power, greater than the first detection power, over the first set of wires (1020); during the second time period, obtaining a second indication of the power attribute over the first set of wires (1030); determining a first difference between the first indication and the second indication (1040); and controlling a first power enable circuit and a second power enable circuit to provide power to the powered device over the first and second sets of wires respectively, responsive to the determined difference (1050).