PoE Mark and Hold System for Rapid Power Restoration
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Solution Overview
Problem
In Power over Ethernet (PoE) systems, the time required for detection and classification of connected devices can be lengthy, leading to delays in power reconnection, especially in applications like lighting, where immediate power restoration is necessary. Additionally, maintaining a minimal current signature to indicate device connection increases costs due to the need for communication between the Powered Device (PD) and Power Sourcing Equipment (PSE).
Innovation Solution
A mark and hold system is introduced, where after detection and classification, the main power supply is disconnected, and the PD is connected to a mark voltage power supply. A detection current source draws current through a port resistance, monitoring the voltage across this resistance to determine if the PD is connected, eliminating the need for continuous communication and reducing power consumption by using a lower voltage for standby mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PSE performs detection and classification before providing power to the PD, then the system ensures proper device identification and power allocation, but the power reconnection time increases to up to a second
Solution Approach 1:
The system performs detection and classification in advance before disconnecting power. When the PD is removed, the PSE already has the classification information stored, so it can immediately reconnect power without repeating the detection and classification process, reducing reconnection time to near-zero while maintaining identification accuracy
Solution Approach 2:
The PSE creates a copy of the PD classification information and stores it in memory after initial detection. This copied information is then reused for rapid reconnection decisions without needing to re-detect the device, eliminating the time penalty while preserving reliable device identification
2Loss of time
If the PD draws minimal current to maintain standby state, then the PSE can detect device presence without full detection cycles, but communication between PSE host and PD is required which increases system cost
Solution Approach 1:
The PD autonomously draws a minimal maintenance current (I_MAINT) to indicate its presence without requiring any communication protocol interaction with the PSE host. The PSE detects this current to determine device presence, eliminating the need for complex communication interfaces while enabling rapid detection
Solution Approach 2:
The invention extracts the essential function of device presence indication from the complex communication protocol requirement. By using a simple minimal current draw as the presence signal, it removes the need for PSE host-PD communication infrastructure, reducing system complexity and cost
3Speed
If the PSE monitors MPS current to maintain power connection, then rapid device presence detection is achieved, but the system requires additional communication infrastructure that increases cost
Solution Approach 1:
The PD self-generates the detection signal by drawing maintenance current I_MAINT, which the PSE monitors to determine device presence. This eliminates the need for external communication systems, achieving rapid detection without additional communication infrastructure
Solution Approach 2:
The invention replaces the communication protocol-based presence detection mechanism with an electrical current-based detection mechanism. The minimal maintenance current serves as a direct electrical signal for device presence, substituting complex communication systems with simple electrical monitoring
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
This solution allows for rapid power restoration in PoE systems by eliminating the need for repeated detection and classification, reducing power consumption, and eliminating the necessity for communication between the PSE host and PD, while maintaining device connection status without significant voltage changes.
Implementation Method 1
A detection current source draws current through a port resistance, monitoring the voltage across this resistance to determine if the PD is connected
Data Source
AI summary
A mark and hold system comprising a main power supply, a mark voltage power supply and a detection current source. After detection, and optionally classification, the main power supply is disconnected from the PD and instead the PD is connected to the mark voltage power supply. The detection current source draws current through a port resistance of the PSE and the PD. The voltage across the port resistance is monitored to determine whether the PD is still connected to the port.