Multi-Spiral Layer Common Mode Filter for High Impedance
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Solution Overview
Problem
Existing thin film common mode filters face challenges in achieving higher common mode impedance and different cutoff frequencies due to limitations in coil structure modifications, which hinders their application in portable electronic devices.
Innovation Solution
A common mode filter with a multi-spiral layer structure is developed, comprising multiple coils connected in series with insulating layers, where at least one of the insulating layers includes magnetic material, allowing for increased impedance without requiring additional space, and a method for manufacturing this filter involves forming coils and insulating layers with magnetic material integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of windings is increased to achieve higher common mode impedance, then the common mode impedance is improved, but the space required for the filter increases
Solution Approach 1:
The patent transitions from a planar coil structure to a three-dimensional multi-layer spiral structure. By stacking multiple spiral coils vertically (first, second, third, and fourth coil layers) and connecting them in series, the filter achieves higher common mode impedance without increasing the horizontal footprint. This vertical dimensionality change allows compact integration while maintaining high impedance performance.
Solution Approach 2:
The patent embeds multiple coil structures within each other in a nested configuration. The first and second coils are positioned at different vertical levels with overlapping horizontal projections, and the third and fourth coils similarly nest at another level. This nested arrangement maximizes the use of vertical space, allowing four complete coil windings to fit within the area that would traditionally accommodate only one or two coils.
2Adaptability or versatility
If the coil structure is modified to achieve different cutoff frequencies, then the filtering performance is improved, but the device complexity increases
Solution Approach 1:
The patent introduces magnetic material portions at specific localized positions between the coil layers rather than uniformly throughout the structure. The magnetic material is strategically placed in the spaces between the first and second coils, and between the third and fourth coils, to locally enhance magnetic flux concentration. This localized modification allows tuning of the cutoff frequency without requiring complete redesign of the entire coil structure.
Solution Approach 2:
The patent combines conductive coil materials with magnetic materials to create a composite filter structure. The magnetic material portions are integrated between the coil layers to form a composite structure that leverages both the electrical properties of the conductive coils and the magnetic properties of the magnetic material. This composite approach enables frequency tuning while maintaining structural simplicity.
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 multi-spiral layer structure effectively increases common mode impedance and allows for flexible adjustment of differential mode cutoff frequencies, enhancing filtering performance without increasing the filter's size, making it suitable for portable electronic devices.
Implementation Method 1
The magnetic material portion is formed through the first, second, third, and fourth coils
Implementation Method 2
The first insulating layer is configured to separate the first coil from the second coil. The second insulating layer is configured to separate the second coil from the third coil. The third insulating layer is configured to separate the third coil from the fourth coil
Data Source
AI summary
A common mode filter includes a first coil, a second coil, a first insulating layer separating the first coil from the second coil, a third coil serially connected with the first coil, a second insulating layer separating the second coil from the third coil, a fourth coil serially connected with the second coil, and a third insulating layer separating the third coil from the fourth coil. The second coil is between the first and third coils, and the third coil is between the second and fourth coils. At least one of the first insulating layer, the second insulating layer and the third insulating layer may include magnetic material.