Coil Component Asymmetric Winding for Mode Conversion
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Solution Overview
Problem
Conventional winding-type common-mode choke coils face challenges in improving radio-frequency characteristics, particularly in the low-frequency band, as further development of techniques to suppress parasitic capacitance is insufficient to enhance coil characteristics.
Innovation Solution
The coil component design features a core with a first wire wound in a helical shape to contact the core's peripheral surface and a second wire wound outside the first layer, with the first coil length being longer than the second coil length, to minimize the difference in inductance values between the two wires, thereby improving the coil's characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both wires are wound with the same coil length, then the manufacturing process is simple, but the inductance values of the two wires become significantly different, degrading the mode conversion characteristic
Solution Approach 1:
The patent applies asymmetry by intentionally making the coil lengths of the first and second wires different. Specifically, the first wire has a longer coil length than the second wire, which compensates for the difference in inductance caused by their different positions (one contacting the core, the other outside). This asymmetric design equalizes the total inductance values, improving the mode conversion characteristic.
Solution Approach 2:
The patent changes the physical parameter of coil length to adjust the inductance values. By extending the coil length of the first wire relative to the second wire, the inductance of the first wire increases, balancing the inductance difference between the two wires and thereby improving the common-mode noise suppression characteristic.
2Reliability
If techniques to suppress parasitic capacitance are further developed, then radio-frequency characteristics may improve, but low-frequency band characteristics cannot be improved by the same techniques
Solution Approach 1:
The patent applies local quality by optimizing the winding structure specifically for low-frequency performance. The different coil lengths are designed to equalize inductance values in the low-frequency band, where inductance matching is critical for common-mode noise suppression. This localized optimization for low-frequency characteristics distinguishes it from general high-frequency parasitic capacitance suppression techniques.
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 reduces the difference in inductance values between the first and second wires, enhancing the mode conversion characteristic Sds21, particularly in the low-frequency region, and improving the overall coil performance.
Implementation Method 1
a first wire and a second wire that are wound around the core part from the first end portion to the second end portion in substantially helical shapes
Data Source
AI summary
A coil component includes a core that includes a core part having a first end portion and a second end portion; and a first wire and a second wire that are wound around the core part from the first end portion to the second end portion in substantially helical shapes so as to have substantially the same number of turns. The first wire is wound so as to form a first layer that contacts the peripheral surface of the core part, the second wire is wound such that at least part of the second wire forms a second layer on the outside of the first layer, and a first coil length formed by the first wire is longer than a second coil length formed by the second wire.