Twisted Winding Coil Layout for Balanced Stray Capacitance
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Solution Overview
Problem
In winding-type coil components, such as common mode choke coils, the stray capacitance between wires and a mount board is not balanced, leading to differences in capacitance that deteriorate mode conversion characteristics.
Innovation Solution
A winding-type coil component with a core having flange portions and wires wound around it, where the wires are twisted and their positions shifted in the circumferential direction to equalize the length of wire portions closer to the mount board, reducing the difference in stray capacitance between the wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two wires are formed into a twisted wire with the same disposition in all turns, then the twisting operation and winding operation can be performed in synchronism during mass production, but the stray capacitance between the mount board and one wire becomes significantly larger than that of the other wire, deteriorating mode conversion characteristics
Solution Approach 1:
The patent applies dynamics by making the disposition of wires dynamic across different turns rather than static and identical. Specifically, the wire closer to the mount board alternates between the first wire in odd-numbered turns and the second wire in even-numbered turns. This dynamic arrangement ensures that both wires experience similar average stray capacitance to the mount board across the entire coil, preventing cumulative capacitance imbalance while maintaining synchronized twisting and winding operations during mass production.
2Shape
If the first and second wires are formed into a twisted wire, then the form of both wires can be made substantially the same, but the stray capacitance between the mount board and each wire remains unbalanced, leading to large capacitance differences
Solution Approach 1:
The patent resolves this contradiction by introducing dynamic alternation in wire disposition across turns. While both wires maintain the same twisted form and structure (satisfying shape uniformity), their relative positions to the mount board alternate systematically: the first wire is closer in odd turns while the second wire is closer in even turns. This dynamic positioning balances the average stray capacitance experienced by both wires to the mount board, eliminating cumulative capacitance imbalance without compromising wire form uniformity.
Data Source
AI summary
A winding-type coil component includes a first wire and a second wire having a twisted wire portion where the first wire and the second wire are twisted together. Switching positions of the first wire and the second wire in the twisted wire portion are shifted in a circumferential direction of a winding core portion every turn.