Integrated Ethernet Coupler with Common Mode Chokes for Emission Control
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Solution Overview
Problem
Higher speed Ethernet over twisted pair networks face challenges in complying with stringent emission standards due to increased radiated interference, particularly in residential settings where devices must meet FCC and IEC standards for conducted and radiated emissions.
Innovation Solution
The use of a combination of common mode chokes and transformers in Ethernet couplers, where a first common mode choke is placed between the PHY and the primary transformer winding, and a second common mode choke between the transformer secondary and the twisted pair, effectively reducing noise across a range of frequencies, including low and high frequencies, and is designed to handle Power over Ethernet currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher speed Ethernet is implemented over twisted pair cable, then data transmission speed is improved, but radiated interference and emissions increase
Solution Approach 1:
The patent introduces common mode chokes as intermediary components between the Ethernet PHY and transformer, and between the transformer and twisted pair cable. These chokes act as mediators that block common mode noise and radiated interference while allowing differential mode data signals to pass through, thus resolving the contradiction between high-speed data transmission and radiated emissions compliance
Solution Approach 2:
The patent extracts and removes harmful common mode noise and radiated interference from the signal path using common mode chokes. By selectively eliminating only the harmful frequency components while preserving the useful data transmission signals, the system achieves both high speed performance and emissions compliance
2Object-generated harmful factors
If common mode chokes are added to reduce noise, then emissions compliance is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple common mode chokes and the transformer into a single integrated Ethernet coupler assembly. By merging these noise reduction components into one unified device rather than separate additions, the patent achieves emissions compliance while minimizing the increase in device complexity
Solution Approach 2:
The common mode chokes serve multiple functions simultaneously: they block common mode noise, filter radiated interference, and allow differential mode data signals to pass. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving emissions compliance
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 configuration provides an additional 5 to 10 dB of noise reduction and ensures compliance with emission standards, while also supporting Power over Ethernet by appropriately handling DC power currents without saturating the transformer.
Implementation Method 1
a first common mode choke is placed between the PHY and the primary transformer winding, and a second common mode choke between the transformer secondary and the twisted pair, effectively reducing noise across a range of frequencies
Implementation Method 2
Ethernet coupling TITLE Magnetic coupling used in Ethernet over twisted pair networks
Implementation Method 3
designed to handle Power over Ethernet currents... appropriately handling DC power currents without saturating the transformer
Data Source
AI summary
Improved coupler for Ethernet over twisted pair. An improved coupler has a first common mode choke for connecting an Ethernet PHY to the primary winding of a transformer. The secondary winding of the transformer connects through a second common mode choke for connection to a twisted pair line. In one embodiment, the first common mode choke, transformer, and second common mode choke are placed in the same package. In a second environment, a plurality of choke-transformer-choke units are placed in the same package. In a third embodiment, the plurality of choke-transformer-choke units may be integrated into a connector. Pairs of the second common mode chokes may share cores.