PoE Powered Device Rectifier Circuit with Dynamic MOSFET Control
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Solution Overview
Problem
In high-power Power over Ethernet (PoE) scenarios using four wire pairs, rectifier circuits in powered devices (PDs) often cause detection errors, preventing normal operation due to incorrect voltage detection.
Innovation Solution
The addition of control circuits to the rectifier circuit in PDs, which manage the turning on/off of MOSFETs based on voltage thresholds, preventing detection errors and reducing power loss by controlling the rectification process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If four wire pairs are used for high-power PoE supply, then power supply capability is improved, but detection errors occur due to rectifier circuit interference
Solution Approach 1:
The patent introduces a control circuit as an intermediary between the rectifier circuit and the detection mechanism. This control circuit monitors the voltage on the wire pairs and selectively activates or deactivates the rectifier circuit based on whether the voltage exceeds a threshold value, thereby preventing the rectifier from interfering with detection operations while maintaining high-power supply capability when needed
Solution Approach 2:
The patent implements dynamic control of the rectifier circuit by making its activation state variable rather than fixed. The rectifier circuit is dynamically enabled or disabled based on real-time voltage conditions, allowing the system to adapt between detection mode (rectifier off) and power supply mode (rectifier on), thus resolving the contradiction between detection accuracy and power supply capability
2Power
If rectifier circuit is always on for power supply, then power delivery is improved, but detection operations fail due to voltage interference
Solution Approach 1:
The patent implements periodic switching between detection and power delivery modes. The control circuit periodically monitors voltage levels and alternates the rectifier circuit between active and inactive states, ensuring that detection operations can occur without interference while maintaining the ability to deliver power when voltage thresholds are exceeded
Solution Approach 2:
The control circuit performs preliminary voltage detection before activating the rectifier circuit. By checking whether the voltage exceeds the threshold in advance, the system prevents the rectifier from being activated during detection operations, thereby ensuring detection reliability while preparing for subsequent power delivery when conditions are appropriate
3Measurement precision
If control circuits are added to manage MOSFET switching, then detection accuracy and power efficiency are improved, but device complexity increases
Solution Approach 1:
The control circuit is designed to perform multiple functions: it monitors voltage levels, determines whether detection or power delivery is appropriate, and controls the switching of MOSFETs in the rectifier circuit. By consolidating these functions into a single multi-functional control unit, the patent improves detection accuracy and power efficiency while minimizing the increase in overall device complexity
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
Ensures accurate detection and reduced power loss during power supply stages, allowing PDs to function correctly even in high-power PoE scenarios.
Implementation Method 1
a rectifier circuit, and a PD circuit, where the Ethernet port is connected to the rectifier circuit; the rectifier circuit is connected to the PD circuit
Implementation Method 2
the rectifier circuit includes a first metal-oxide semiconductor field-effect transistor MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET
Data Source
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AI summary
This application discloses a powered device (PD) used for power over Ethernet (PoE). The PD includes an Ethernet port and a rectifier circuit. The rectifier circuit includes a first control circuit and a second control circuit, the first control circuit is configured to: control a first MOSFET and a second MOSFET, skip turning on the first MOSFET and the second MOSFET at a PoE detection stage, and turn on at least one of the first MOSFET and the second MOSFET at a PoE power supply stage. The second control circuit is configured to: control a third MOSFET and a fourth MOSFET, turn on at least one of the third MOSFET and the fourth MOSFET at the PoE power supply stage, and skip turning on the third MOSFET and the fourth MOSFET at the PoE detection stage.