Common Mode Choke Coil Magnetic Gap Design
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Solution Overview
Problem
Conventional common mode choke coils with ferrite magnetic cores experience magnetic loss and reduced quality factor at high frequencies, leading to decreased common mode impedance and resonance frequency attenuation.
Innovation Solution
Incorporating non-magnetic layers and strategically positioned magnetic gaps between the ferrite magnetic core and coil conductors to minimize magnetic flux leakage, thereby reducing magnetic loss and maintaining high-frequency impedance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ferrite magnetic core is used to increase common mode impedance, then common mode noise attenuation is improved, but magnetic loss occurs at high frequencies causing quality factor degradation
Solution Approach 1:
The magnetic core is segmented into multiple sections with non-magnetic material layers inserted between them. This segmentation creates magnetic gaps that reduce magnetic flux density in the gaps, thereby reducing magnetic loss at high frequencies while maintaining the overall magnetic core structure for common mode impedance.
Solution Approach 2:
Non-magnetic material layers are introduced as intermediary elements between magnetic core sections. These intermediary layers create magnetic gaps that mediate the magnetic flux path, reducing the concentration of magnetic flux and associated losses in any single region while preserving the magnetic coupling needed for noise attenuation.
2Reliability
If magnetic core is used to achieve large common mode impedance, then noise attenuation is improved, but resonance frequency peak value decreases due to magnetic loss
Solution Approach 1:
The magnetic core is divided into multiple sections separated by non-magnetic layers, creating a segmented structure. This segmentation reduces magnetic loss by distributing the magnetic flux across multiple paths with gaps, thereby maintaining resonance frequency peak values and improving the precision of impedance characteristics at high frequencies.
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 suppresses the decrease in peak common mode impedance and increases the resonance frequency, enhancing the choke coil's noise attenuation performance.
Implementation Method 1
a magnetic core that is made of a ferrite material and connects said pair of magnetic layers to each other, and a plurality of coil conductors embedded in said insulator layer so as to be wound around the magnetic core
Implementation Method 2
magnetic loss occurs in the magnetic core made of a ferrite material, so that a quality factor in a high-frequency band becomes lower
Data Source
AI summary
In a common mode choke coil having a magnetic core, a decrease in peak value of a common mode impedance in a vicinity of its resonance frequency is suppressed. A common mode choke coil includes a non-magnetic layer, a first magnetic layer formed on a top surface of the non-magnetic layer, a second magnetic layer formed on a bottom surface of the non-magnetic layer, a magnetic core provided between the first magnetic layer and the second magnetic layer so that its axis extends in a top-bottom direction, a first coil conductor embedded in the non-magnetic layer and wound around the magnetic core, a second coil conductor embedded in the non-magnetic layer and wound around the magnetic core, and a first magnetic gap provided between a top surface of the magnetic core and a bottom surface of the first magnetic layer. The magnetic core is made of a ferrite material.