Slim PCB EMI Filter Layout for Coil Polarity Matching
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Solution Overview
Problem
Conventional slim-type EMI filters require changes to circuit board configurations to connect primary and secondary coils with the same polarity, increasing design complexity and reducing efficiency.
Innovation Solution
A slim-type EMI filter design with a core unit and coil units featuring overlapping conductive patterns in a vertical direction, allowing for polarity matching without altering the circuit board configuration, and a circuit board incorporating this EMI filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a slim-type EMI filter is used with PCB coils sharing a center leg of magnetic core, then the thickness is reduced, but the circuit board configuration must be changed to connect input lines with opposite polarities, increasing design difficulty
Solution Approach 1:
The patent inverts the conventional connection approach by using opposite polarity connections on the PCB coils to achieve the same common-mode noise filtering effect, thereby maintaining the slim form factor without requiring complex circuit board reconfiguration. The first and second PCB coils are connected with opposite polarities, which simplifies the overall design while achieving the desired EMI filtering performance.
Solution Approach 2:
The patent introduces asymmetry in the connection configuration of the PCB coils, where the first and second coils are connected with opposite polarities rather than the conventional same polarity connection. This asymmetric connection approach allows the slim-type EMI filter to function effectively without requiring changes to the circuit board configuration, thus resolving the technical contradiction between reduced thickness and design complexity.
2Device complexity
If input lines with opposite polarities are connected in slim-type EMI filter, then circuit board design is simplified, but inductance asymmetry may occur affecting efficiency
Solution Approach 1:
The patent carefully controls the geometric parameters of the first and second PCB coils, including their dimensions, winding patterns, and positions relative to the magnetic core. By optimizing these parameters, the patent ensures that the inductance values of both coils remain balanced despite the opposite polarity connection, thereby preventing inductance asymmetry and maintaining power supply efficiency while simplifying the circuit board design.
Solution Approach 2:
The patent applies different local configurations to the first and second PCB coils, such as varying their positions, orientations, or winding directions, to compensate for the opposite polarity connection. This local quality adjustment ensures that the overall inductance balance is maintained, preventing efficiency loss while allowing for simplified circuit board integration of the slim-type EMI filter.
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
Facilitates polarity matching between primary and secondary coils, preventing inductance asymmetry and maintaining efficiency, while maintaining a slim form factor.
Implementation Method 1
a first lower conductive pattern disposed on the lower surface of the first substrate... a second upper conductive pattern disposed on the upper surface of the second substrate... at least a portion of the second upper conductive pattern and at least a portion of the second lower conductive pattern intersect each other when viewed in a plan view
Data Source
AI summary
An inductor according to an embodiment includes a core unit and a coil unit wherein a first coil unit includes a first upper conductive pattern and a first lower conductive pattern, wherein the second coil unit includes a second upper conductive pattern and a second lower conductive pattern, wherein the coil unit includes a center portion, a first pattern lead-out portion, and a second pattern lead-out portion, and wherein, in the second pattern lead-out portion, the second upper conductive pattern and the second lower conductive pattern overlap each other in a vertical direction such that at least a portion of the second upper conductive pattern and at least a portion of the second lower conductive pattern intersect each other when viewed in a plan view.