Ethernet PHY to ICM Connection Without Common Mode Choke
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Solution Overview
Problem
The existing Ethernet apparatuses with integrated connector modules (ICMs) that include common mode chokes are costly and can interfere with PCB organization due to size constraints and manual winding requirements, and removing the choke can lead to signal skew issues.
Innovation Solution
The Ethernet physical transceiver (PHY) to ICM connection uses four pairs of signal traces routed to be relatively the same length on a printed circuit board (PCB) without a common mode choke, minimizing skew and allowing better PCB organization, and the PoE connections are grouped by port to reduce congestion and disorganization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common mode choke is included in the integrated connector module, then common mode noise is removed and signal isolation is improved, but device cost increases and PCB organization becomes difficult due to size constraints and manual winding requirements
Solution Approach 1:
The patent extracts the common mode choke function from the integrated connector module by routing signal traces directly from the Ethernet PHY to the ICM without passing through a CMC. This eliminates the manual winding requirement and size constraints while maintaining common mode noise removal through alternative trace routing techniques.
Solution Approach 2:
The patent introduces PCB signal traces as an intermediary medium to replace the common mode choke's noise filtering function. By carefully routing these traces with controlled impedance and length matching, the system achieves common mode noise rejection without requiring a physical choke component.
2Reliability
If a common mode choke is included in the integrated connector module, then signal isolation is improved, but device size and cost increase
Solution Approach 1:
The patent removes the common mode choke from the ICM assembly entirely, extracting its magnetic isolation function and replacing it with PCB trace routing. This eliminates the additional device size and weight while maintaining signal isolation through the inherent shielding and routing design of the PCB.
3Ease of manufacture
If signal traces are routed to be the same length without a common mode choke, then PCB organization is improved and cost is reduced, but signal skew may increase
Solution Approach 1:
The patent applies length matching techniques to ensure all differential signal traces have equal lengths, creating equipotential signal paths. This compensates for the removal of the common mode choke by ensuring that both sides of the differential pair experience identical signal propagation conditions, thereby eliminating skew without requiring a choke.
Solution Approach 2:
The patent implements localized trace routing optimizations at critical points in the signal path, such as using controlled impedance sections and adjusting trace widths or lengths in specific areas to compensate for routing differences. This maintains signal integrity and minimizes skew without requiring uniform routing throughout the entire PCB.
Data Source
AI summary
Disclosed herein is a technique for a connection from an Ethernet physical transceiver (PHY) to an integrated connector module (ICM) where the connection and the ICM lack a common mode choke. The ICM can include a magnetic coupler that directly couples an Ethernet jack and the PHY.