Pre-detection Voltage for Ethernet Powered Device Transient Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Ethernet networks, the connection or disconnection of powered devices can cause harmful voltage and current transients due to asymmetric connections, potentially damaging equipment by creating an unintended unbalanced discharge path, especially when probing for a valid powered device detection signature.
Innovation Solution
A pre-detection stage is implemented that applies a very low voltage to the output port to determine if a device is connected, only initiating the probing routine if the impedance or voltage is within a specific range, thereby preventing high open circuit voltages from appearing across open terminals and minimizing transients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probing routine is initiated to detect a valid powered device detection signature, then device detection capability is improved, but harmful voltage and current transients may be generated causing equipment damage
Solution Approach 1:
The patent applies preliminary action by implementing a pre-detection stage that measures impedance before initiating the full probing routine. This preliminary impedance measurement identifies potential powered devices without applying high detection voltages, thereby avoiding harmful transients while still enabling accurate device detection when a valid powered device is present
Solution Approach 2:
The patent changes the electrical parameters applied during detection by using different voltage levels for different detection stages. A lower voltage is used during the pre-detection impedance measurement stage, while higher voltages are only applied during the probing routine after a potential powered device has been identified, thus balancing detection accuracy with transient prevention
2Measurement precision
If high open circuit voltage is applied during probing for valid powered device detection signature, then detection accuracy is improved, but equipment damage risk increases due to asymmetric connections
Solution Approach 1:
The patent performs preliminary impedance measurements at lower voltages before applying high detection voltages. This preliminary action identifies potential powered devices and prepares the system to apply high voltages only when safe, thus maintaining detection accuracy while preventing equipment damage from asymmetric connections
Solution Approach 2:
The patent introduces an intermediary impedance measurement stage that acts as a mediator between the low-voltage safe state and the high-voltage detection state. This intermediary stage provides a safe transition path that maintains detection capability while preventing direct exposure to harmful transients during connection establishment
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 approach effectively prevents harmful transients during device connection or disconnection by ensuring that the probing routine is only initiated when a valid device is detected, reducing the risk of equipment damage and maintaining network integrity.
Implementation Method 1
comparing the indication of the pre-detection output voltage with a pre-determined value; and in the event that the indication of the pre-detection output voltage is less than the pre-determined value; initiating a probing routine
Implementation Method 2
A pre-detection stage is implemented that applies a very low voltage to the output port to determine if a device is connected, only initiating the probing routine if the impedance or voltage is within a specific range
Data Source
AI summary
A method and apparatus for preventing harmful transients resulting from a probing routine for a valid powered device detection signature in a network, the method comprising: operating power sourcing equipment to provide via its output port a pre-detection output voltage; obtaining an indication of the pre-detection output voltage; comparing the indication of the pre-detection output voltage with a pre-determined value; and in the event that the indication of the pre-detection output voltage is less than the pre-determined value; initiating a probing routine for a valid powered device detection signature. The higher voltage of the probing routine is thus not present at the output port in the absence of pre-detection of a potentially valid powered device detection signature.