POE Identification Circuit Prevents Overload Power-Off
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Solution Overview
Problem
In Power over Ethernet (POE) systems, there is a risk of overload power-off when a powered device designed for a higher power standard is connected to a power sourcing equipment designed for a lower power standard, as the power sourcing equipment cannot provide the required power, leading to potential device malfunction or failure.
Innovation Solution
An identification circuit that detects the power level provided by the power sourcing device, using a charge retention module, load module, and overload detection module to determine if the power sourcing equipment is overloaded, generating identification signals to prevent excessive power draw and ensuring the powered device operates within the capabilities of the power sourcing equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a powered device is designed for the higher power standard 802.3at (25.5W), then the device can operate at higher power levels, but if connected to a power sourcing equipment designed for the lower power standard 802.3af (12.95W), overload power-off occurs due to insufficient power supply capability
Solution Approach 1:
The patent applies preliminary action by implementing an identification circuit that performs power capability detection before the powered device begins normal power consumption. The circuit actively tests the power sourcing equipment's capability by monitoring voltage drops during a detection period, determining whether the equipment supports 802.3at (25.5W) or only 802.3af (12.95W) standards. This preliminary detection prevents overload power-off by ensuring the device configures its power consumption to match the actual supply capability before full operation begins.
2Adaptability or versatility
If the powered device requests 25.5W power based on 802.3at standard, then the device can achieve full performance, but the power sourcing equipment designed for 802.3af cannot provide sufficient power, causing overload shutdown
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the powered device's power consumption parameters based on the detected power sourcing equipment capability. The identification circuit measures the voltage drop across a known resistance during a detection period and compares it against threshold values to determine the power standard. Based on this detection, the device adapts its power request parameter - requesting up to 25.5W for 802.3at-compatible equipment or limiting to 12.95W for 802.3af equipment - thereby achieving compatibility across different power standards while preventing overload shutdown.
3Reliability
If the powered device limits power consumption to match lower power capability, then overload power-off is prevented, but the device cannot utilize full performance capabilities when connected to higher power equipment
Solution Approach 1:
The patent applies feedback by implementing a detection mechanism that actively queries the power sourcing equipment's capability and uses this information to configure the powered device's power consumption. The identification circuit monitors voltage characteristics during a detection period and provides feedback about the power standard (802.3at or 802.3af) to the device's power management system. This feedback loop ensures the device requests appropriate power levels - maximizing performance at 25.5W when connected to 802.3at equipment while preventing overload at 12.95W when connected to 802.3af equipment - thereby resolving the contradiction between reliability and productivity.
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
Prevents overload power-off by accurately identifying the power capabilities of the power sourcing equipment, allowing the powered device to limit its power consumption to match the available supply, ensuring stable operation and preventing device failure.
Implementation Method 1
a charge retention module configured to generate a control voltage from the input voltage, wherein the control voltage is configured to ramp from zero to a threshold voltage value over a test period
Implementation Method 2
the control voltage is configured to ramp from zero to a threshold voltage value over a test period
Implementation Method 3
an overload detection module connected to receive the input voltage to detect whether the input voltage has dropped to zero during the test period
Data Source
AI summary
An electronic detection circuit for detecting a power level provided by a power sourcing device to a powered device in a Power over Ethernet (POE) system, the electronic detection circuit comprising a power input end, a power output end, a charge retention module configured to generate a control voltage from the input voltage, a load module configured to draw power at a test power level from the power sourcing device, a connection switch, and an overload detection module connected to receive the input voltage to detect whether the input voltage has dropped to zero during the test period.