Multimedia Interface Connector EMI Reduction via Auxiliary Ground
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Solution Overview
Problem
High Definition Multimedia Interface (HDMI) connectors suffer from electromagnetic interference (EMI) due to the absence of EMI reduction technology, leading to noise that exceeds EMC radiation standards, primarily caused by the HDMI clock signal.
Innovation Solution
A multimedia interface connector design that includes a main ground and an auxiliary ground arranged between the connection terminal and the printed circuit board (PCB) to form a return path for signals, with the auxiliary ground adjacent to the clock terminal, reducing EMI by shortening the return path and altering resonance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If HDMI connector uses conventional ground design, then device complexity is low, but electromagnetic interference radiation exceeds EMC standards
Solution Approach 1:
The ground structure is segmented into multiple functional grounds: main ground for general reference, auxiliary ground for signal return paths, and clock ground for clock signal reference. This segmentation isolates different signal types and their return currents, preventing EMI radiation while maintaining manageable complexity through organized functional separation.
Solution Approach 2:
The auxiliary ground acts as an intermediary element between the main ground and the signal lines. It provides a dedicated return path for signal currents, mediating the current flow to prevent direct coupling between signal lines and the main ground, thereby reducing EMI radiation without requiring complete redesign of the entire grounding system.
2Object-affected harmful factors
If auxiliary ground is added to reduce EMI, then EMI radiation decreases, but manufacturing complexity increases
Solution Approach 1:
The auxiliary ground is merged with the existing main ground structure at strategic points, forming a unified ground system with differentiated functional zones. This merging approach allows the auxiliary ground to provide specialized return paths while ultimately connecting to the main ground, simplifying manufacturing by eliminating the need for completely separate ground systems and reducing assembly 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
The solution effectively reduces EMI radiation, ensuring compliance with EMI criteria by minimizing resonance frequencies and maintaining a safe electromagnetic compatibility level.
Implementation Method 1
an auxiliary ground arranged between the main ground and the PCB to form a return path for a signal received through the connection terminal
Implementation Method 2
resonance characteristics appear at a frequency of 891 MHz resulting from ×3 multiplication of a pixel frequency of 297 MHz
Data Source
AI summary
A multimedia interface connector includes a connection terminal in electrical connection with a printed circuit board (PCB); a main ground partially enclosing a first end of the connection terminal; and an auxiliary ground arranged between the main ground and the PCB to form a return path for a signal received through the connection terminal, wherein a second end of the connection terminal and the main ground are connected to the PCB.