Circuit Board Ground Pattern Segmentation for Signal Balance
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Solution Overview
Problem
The existing configuration of circuit boards with common mode filters often results in degraded signal quality due to variations in capacitance components caused by land patterns overlapping ground patterns, leading to poor Sdc11 characteristics.
Innovation Solution
A circuit board design where the first and second land patterns do not overlap the ground pattern, with a specific wiring layer configuration that includes input and output wiring patterns connected to terminal electrodes, and a ground pattern that overlaps the wiring patterns without overlapping the land patterns, reducing capacitance variations and improving signal balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the ground pattern overlaps the land patterns to maintain signal balance, then signal symmetry is improved, but capacitance variation increases causing degraded Sdc11 characteristics
Solution Approach 1:
The ground pattern is segmented into two distinct regions: a first ground pattern that overlaps with the third and fourth land patterns (output side) to maintain signal balance, and a second ground pattern that is disposed to overlap the wiring patterns but not the first and second land patterns (input side) to minimize capacitance variation. This segmentation allows different parts of the ground pattern to serve different functions.
Solution Approach 2:
Different regions of the ground pattern are designed with different overlapping characteristics: the first ground pattern overlaps the output land patterns to provide local signal balance, while the second ground pattern avoids overlapping the input land patterns to minimize local capacitance variation. This local differentiation resolves the contradiction between global signal balance and local capacitance stability.
2Stability of the object's composition
If the entire differential signal line overlaps the ground pattern, then signal symmetry is maintained, but signal quality degrades due to capacitance variations
Solution Approach 1:
The ground pattern coverage is segmented such that it provides overlapping coverage for the output wiring patterns and third/fourth land patterns, while intentionally creating a non-overlapping region for the input wiring patterns and first/second land patterns. This selective segmentation maintains signal symmetry where needed while avoiding capacitance-induced quality degradation.
Solution Approach 2:
The ground pattern is designed with spatially varying properties: full overlapping coverage in output regions for signal symmetry, and non-overlapping coverage in input regions for signal quality. This local quality differentiation allows the system to optimize different segments for different performance criteria.
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 enhances signal quality by minimizing capacitance variations and improving Sdc11 characteristics, leading to better signal balance and high-frequency performance.
Implementation Method 1
a capacitance component generated in a land pattern causes the above phenomenon
Data Source
AI summary
Disclosed herein is an electronic circuit module that includes a circuit board and a common mode filter mounted on the circuit board. The common mode filter includes first and second terminal electrodes constituting a first pair of terminal electrodes and third and fourth electrodes constituting a second pair of terminal electrodes. The circuit board includes: a first wiring layer having first, second, third, and fourth land patterns connected to the first, second, third, and fourth terminal electrodes, respectively, and first, second, third, and fourth wiring patterns connected to the first, second, third, and fourth land patterns, respectively; and a second wiring layer having a ground pattern that overlaps the first, second, third, and fourth wiring patterns without overlapping the first and second land patterns.