Multilayer Common Mode Noise Filter for Balanced Differential Signals
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Solution Overview
Problem
Existing common mode noise filters experience a decline in mode conversion characteristics due to dispersion in stray capacitance between coils, leading to imbalanced differential signal transmission.
Innovation Solution
A common mode noise filter with a multilayer structure comprising insulator layers and coils, where the coils are arranged such that the intervals between them (I1, I2, and I3) satisfy I1 < I3 and I2 < I3, reducing stray capacitance and maintaining balanced differential signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If coils are arranged close together to reduce device size, then device complexity is reduced, but stray capacitance increases causing mode conversion characteristic degradation
Solution Approach 1:
The patent applies asymmetry by intentionally creating different interval distances between adjacent coils (I1 < I3 and I2 < I3). The third interval I3 is made larger than the first and second intervals, which asymmetrically distributes the stray capacitance. This asymmetric arrangement prevents excessive capacitance coupling while maintaining compact overall device dimensions, thereby resolving the contradiction between device compactness and mode conversion characteristics.
2Manufacturing precision
If uniform intervals are used between all coils, then manufacturing precision is improved, but signal balance deteriorates due to stray capacitance dispersion
Solution Approach 1:
The patent applies local quality by making the interval between the third and fourth coils (I3) different from the intervals between other adjacent coils (I1 and I2). Specifically, I3 is designed to be larger than I1 and I2. This local variation in interval quality allows precise control over stray capacitance distribution, ensuring that the coil with the largest absolute value of differential mode to common mode conversion characteristic has optimized spacing, thereby maintaining signal balance while still using standardized manufacturing processes.
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 effectively reduces stray capacitance, particularly between the third coil and the fourth coil, thereby minimizing the decline in mode conversion characteristics and maintaining signal balance across the differential signals.
Implementation Method 1
first, second, and third coils which are respectively provided for the plurality of non-magnetic layers, and which are independent of each other. The first, second, and third coils have first, second, and third coil conductors, respectively
Implementation Method 2
a plurality of insulator layers stacked one on top of another in an upward/downward direction; and a first coil conductor, a second coil conductor, a third coil conductor, a fourth coil conductor, a fifth coil conductor, and a sixth coil conductor provided for the plurality of insulator layers
Data Source
AI summary
A common mode noise filter includes: a plurality of insulator layers; and a first coil conductor, a second coil conductor, a third coil conductor, a fourth coil conductor, a fifth coil conductor, and a sixth coil conductor. A first interval I1 measured in an upward/downward direction from an upper surface of the first coil conductor to a lower surface of the third coil conductor, a second interval I2 measured in the upward/downward direction from an upper surface of the fourth coil conductor to a lower surface of the sixth coil conductor, and a third interval I3 measured in the upward/downward direction from the lower surface of the third coil conductor to the upper surface of the fourth coil conductor satisfy I1<I3 and I2<I3.