Common Mode Inductor Isolation Gap Segmentation for EMI Suppression
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Solution Overview
Problem
Conventional common mode inductors in switching power supplies face challenges in enhancing EMI noise suppression, particularly as they develop towards smaller and higher frequency designs, where the existing isolation gap configuration in multilayered coil windings is difficult to control and results in instability and reduced EMI noise suppression capability.
Innovation Solution
A common mode inductor design with two multilayered coil windings symmetrically wrapped around a magnetic core, where each winding is divided into two areas by an isolation gap starting from the first layer, and a wrapping method using isolation blocking sheets to maintain the gap's stability and size, enhancing EMI noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional isolation gap configuration is used in multilayered coil windings, then the structure is simpler, but the EMI noise suppression capability deteriorates and stability is reduced
Solution Approach 1:
The patent divides each multilayered coil winding into multiple independent sections using isolation gaps. Specifically, the first and second multilayered coil windings are each divided into first and second coil sections by first and second isolation gaps respectively. This segmentation isolates different parts of the winding, preventing noise propagation and improving EMI suppression capability while maintaining a manageable structural complexity.
2Productivity
If switching power supplies are designed for small size and high frequency, then the power density increases, but the EMI noise suppression becomes more difficult
Solution Approach 1:
The patent applies segmentation by introducing multiple isolation gaps that divide the coil windings into separate sections. This allows the compact high-frequency design to maintain EMI suppression by isolating noise-generating sections from sensitive sections, enabling small size and high frequency operation without sacrificing noise suppression performance.
Solution Approach 2:
The patent implements local quality by placing isolation gaps at specific locations within the coil windings where noise generation or propagation is most critical. The first and second isolation gaps are positioned to create first and second coil sections respectively, providing targeted EMI suppression at key locations rather than requiring uniform complexity throughout the entire structure.
3Manufacturing precision
If isolation gaps are not properly controlled in multilayered coil windings, then the manufacturing is easier, but the stability and EMI noise suppression capability deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-defining the position and dimensions of isolation gaps before the coil winding manufacturing process. The first and second isolation gaps are established as fixed structural elements that divide the windings into controlled sections, ensuring consistent EMI suppression performance across production batches without requiring complex real-time adjustments during manufacturing.
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 proposed design significantly improves EMI noise suppression capability compared to conventional methods, allowing for the development of switching power supplies with better stability and reduced dependency on additional EMI suppression components, leading to a simpler and more cost-effective design for small and high-frequency applications.
Implementation Method 1
The common mode inductor mainly includes a magnetic core 102 and two multilayered coil windings 101 symmetrically wrapped around the magnetic core
Data Source
AI summary
The present disclosure provides a switching power supply, an EMI filter, a common mode inductor and a wrapping method for the common mode inductor. The common mode inductor includes: a magnetic core; two multilayered coil windings symmetrically wrapped around the magnetic core; and two isolation gaps each of which is formed in respective one of the two multilayered coil windings, and is configured to divide, by beginning from a first layer, the respective one of the multilayered coil windings into two wrapping areas.