Powered Device Power Supply Switching Overcurrent Prevention
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Solution Overview
Problem
Existing powered devices that can receive power from multiple sources, such as general-purpose power supplies and Power over Ethernet (PoE) systems, face instability when switching between power sources, leading to potential power interruptions and device resets, particularly when the PoE supply is connected while a general-purpose supply is already active, causing overcurrent issues.
Innovation Solution
A powered device with a configuration that includes separate load units and voltage conversion units, along with a switch unit, allows power to be supplied from either the general-purpose or PoE source without exceeding current limits, ensuring stable operation by isolating the power loads and managing voltage conversions to prevent overcurrents during source changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the powered device switches from general-purpose power supply to PoE power supply, then power source versatility is improved, but overcurrent occurs causing power supply interruption
Solution Approach 1:
The patent divides the load into first and second load units electrically separated from each other. The first load unit is powered by the PoE power supply while the second load unit is powered by the general-purpose power supply. This segmentation allows the device to accept multiple power sources without overcurrent issues, as each load unit is independently powered by its designated supply.
Solution Approach 2:
The patent introduces a changing unit as an intermediary component that manages power supply transitions. The changing unit controls when and how power is switched between the PoE power supply and the general-purpose power supply, preventing direct overcurrent conflicts by mediating the power distribution process.
2Adaptability or versatility
If the powered device uses a single power supply configuration, then device complexity is reduced, but adaptability to multiple power sources is limited
Solution Approach 1:
The patent segments the power supply system into distinct first and second power supply paths with separate load units. This segmentation enables multi-power supply capability while keeping each individual path simple and manageable, avoiding the complexity of a single unified power management system.
Solution Approach 2:
The patent creates a universal power supply configuration where the powered device can operate with either the PoE power supply, the general-purpose power supply, or both simultaneously. The changing unit provides multi-functionality by managing different power supply modes (single supply mode and dual supply mode) without requiring complex redesign.
3Speed
If the powered device immediately switches to PoE power supply upon connection, then power supply response speed is improved, but overcurrent protection function activates causing operation interruption
Solution Approach 1:
The patent applies preliminary action by pre-configuring the changing unit to manage power supply transitions carefully. When PoE power supply is detected, the changing unit first ensures proper power distribution to the first load unit before activating the second load unit from the general-purpose power supply. This preliminary coordination prevents overcurrent issues while maintaining fast response.
Solution Approach 2:
The changing unit acts as an intermediary that mediates between the fast PoE power supply response and the need for continuous stable operation. It controls the timing and sequence of power distribution to prevent overcurrent protection activation while maintaining both speed and reliability.
Data Source
AI summary
A powered device receives power from at least one of a first power supply and a second power supply having a voltage higher than a voltage of the first power supply. The powered device includes a first load unit, a second load unit electrically separated from the first load unit, and a changing unit configured to supply power from the first power supply to the first load unit and the second load unit in a case where the first power supply is connected to the powered device and the second power supply is not connected to the powered device, and supply power from the second power supply to the first load unit and from the first power supply to the second load unit in a case where the first power supply and the second power supply are connected to the powered device.