PoE Current-Sensing Manipulation for 180 W Power Delivery
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Solution Overview
Problem
Existing power over Ethernet (PoE) standards, such as IEEE 802.3bt, limit output power to 90 W, which is insufficient for certain devices like PTZ cameras under cold weather conditions, necessitating additional hardware and cables.
Innovation Solution
A method and system that manipulate the current-sensing device in power sourcing equipment to sense a lower loop current, allowing it to provide higher output power, up to 180 W, while maintaining compatibility with existing PoE standards through power negotiation and manipulation of shunt resistances or inductive circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power sourcing equipment follows IEEE PoE standards with maximum 90 W output, then backward compatibility with existing PoE solutions is maintained, but power is insufficient for certain devices like PTZ cameras under cold weather conditions
Solution Approach 1:
The patent changes the sensing parameter by manipulating the current-sensing device to report a lower loop current than actually flows. This allows the power sourcing equipment to deliver higher power (up to 180 W) while the negotiation protocol still perceives standard power levels, thus maintaining backward compatibility while increasing adaptability to high-power devices
Solution Approach 2:
The current-sensing device acts as an intermediary between the actual power delivery system and the negotiation protocol. By manipulating this intermediary to report falsified current measurements, the system bridges the gap between standard-compliant negotiation and high-power delivery capability
2Power
If additional external power supply is added to provide more than 90 W, then power requirement is met, but additional hardware and power cable are required
Solution Approach 1:
The power sourcing equipment is designed to perform multiple functions: it can deliver both standard PoE power (90 W) and extended power (180 W) through the same hardware interface and negotiation protocol. This eliminates the need for separate power supplies or additional cables, reducing device complexity while maintaining high power capability
3Measurement precision
If the current-sensing device measures actual loop current accurately, then power negotiation is precise according to standards, but the power sourcing equipment cannot deliver increased power beyond standard limits
Solution Approach 1:
The system preemptively manipulates the current-sensing device to prevent the power negotiation protocol from detecting the true high current levels. By falsifying the measurement before negotiation occurs, the system avoids triggering standard protection mechanisms while enabling higher power delivery
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 delivery of increased power to PoE devices without additional hardware, ensuring backward compatibility and supporting devices that exceed standard power limits.
Implementation Method 1
establishing a relation between an output voltage of the power sourcing equipment and a loop current from the powered device to the power sourcing equipment by measuring the loop current in a current-sensing device
Data Source
AI summary
A method for controlling the output power of power sourcing equipment powering a device through an ethernet cable, comprising: performing a power negotiation between the power sourcing equipment and the powered device, the negotiation comprising establishing a relation between an output voltage of the power sourcing equipment and a loop current from the powered device to the power sourcing equipment by measuring the loop current in a current-sensing device; obtaining indications of whether the powered device needs increased power and whether the power sourcing equipment is able to deliver increased power; if the powered device needs increased power and the power sourcing equipment is of a power sourcing equipment type able to deliver increased power, physically manipulating the current-sensing device such that it senses a manipulated lower loop current; and providing a manipulated higher output power from the power sourcing equipment to the powered device.