Power Receiving Apparatus Seamless Source Switching Control
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Solution Overview
Problem
Power receiving apparatuses connected to multiple power sources face issues with overcurrent and power supply interruption during source switching, particularly when transitioning from a general-purpose power source to a Power over Ethernet (PoE) source, as existing technologies fail to manage the current limit effectively during negotiation processes.
Innovation Solution
The power receiving apparatus includes detection units for identifying connected power sources, a voltage conversion unit, and a control unit that manages a switch to ensure seamless power supply transitions, preventing overcurrent by controlling the switch based on detection results and performing negotiation processes within current limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power source is changed over from the first power source to the second power source while all functions are operated by the first power source, then the power receiving apparatus can utilize the second power source, but a current equal to or larger than the limit value of 400 mA flows from the PSE to the PD immediately after the changeover, causing the PSE to stop power supply
Solution Approach 1:
The control unit performs a negotiation process with the PSE before switching power sources, and delays the switch timing until the negotiation is complete. This preliminary action ensures that the PSE is aware of the upcoming power source change and can prepare accordingly, preventing overcurrent conditions that would cause the PSE to stop power supply.
Solution Approach 2:
The system dynamically adjusts the power source switching timing based on the negotiation status with the PSE. The switch timing is not fixed but is determined by the completion of the negotiation process, allowing the system to adapt to different power source conditions and avoid overcurrent situations.
2Speed
If the power receiving apparatus switches to the second power source immediately upon connection, then the switching response is fast, but overcurrent occurs during the negotiation process causing power supply interruption
Solution Approach 1:
The control unit initiates a negotiation process with the PSE before activating the power source switch. This preliminary negotiation establishes current limits and power delivery parameters, ensuring that when the switch activates, the current remains within safe limits and no overcurrent occurs.
Solution Approach 2:
The system uses feedback from the negotiation process to determine the appropriate switch timing. The control unit monitors the negotiation status and adjusts the switch timing accordingly, ensuring that switching occurs only when the PSE is ready to provide power within the agreed current limits, thus preventing overcurrent conditions.
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 enables smooth power source switching without interrupting the power supply to the load, effectively managing current limits during negotiations and preventing overcurrent issues, ensuring stable operation of the power receiving apparatus.
Implementation Method 1
a voltage conversion unit configured to convert a voltage of the power supplied from the second power source
Data Source
AI summary
It is necessary to suppress the interruption of the power supply when the power source is changed. A power receiving apparatus receives power from a first power source or a second power source, and one of power from the first power source and power converted by a voltage conversion unit is supplied to a load unit, based on a result of detection of whether the power receiving apparatus is connected to the first power source, a result of detection of whether the power receiving apparatus is connected to the second power source, and a voltage that can be supplied from the second power source.