Embedded Magnetic Vent Channel Layout for Lower Leakage Inductance
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Solution Overview
Problem
Embedded magnetic component devices face challenges with air bubbles in epoxy gel causing device failure, mechanical stress from thermal expansion differences, and reduced dielectric strength due to air gaps, leading to increased size and leakage inductance issues.
Innovation Solution
The design incorporates a single vent channel with a bottom wall recess and a groove on the opposite side of the magnetic core, allowing the first winding to be closer to the core, with wider traces and overlapping windings to improve isolation and reduce leakage inductance, while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If epoxy gel is used to fill the cavity to secure the magnetic core, then the magnetic core is firmly held in place, but air bubbles form in the epoxy gel causing device failure during reflow soldering
Solution Approach 1:
The patent removes the epoxy gel entirely from the cavity, replacing it with air. This extraction eliminates the air bubble formation problem while the magnetic core is secured through alternative means (adhesive applied to the bottom of the cavity and mechanical constraints from the winding structure) rather than epoxy embedding.
2Reliability
If an air gap is maintained between the magnetic core and cavity sides to eliminate air bubbles, then device reliability is improved, but the spacing between primary and secondary windings must be large reducing isolation value
Solution Approach 1:
The patent applies local quality by concentrating the air gap specifically between the magnetic core and the cavity walls, while maintaining close spacing between windings through precise positioning. The adhesive application to the cavity bottom and the winding structure itself provide localized securing without requiring uniform spacing throughout the cavity.
3Reliability
If multiple channels are provided to vent the cavity, then air bubble removal is improved, but the device size increases and leakage inductance increases
Solution Approach 1:
The patent extracts the epoxy gel that was causing air bubble entrapment, eliminating the need for multiple vent channels. A single channel is sufficient to vent any remaining air, and the overall device size is reduced by removing the epoxy filling material entirely.
4Loss of energy
If the first winding is positioned closer to the magnetic core to reduce leakage inductance, then leakage inductance is reduced, but isolation between windings may be compromised
Solution Approach 1:
The patent applies local quality by creating different spacing relationships in different regions: the first winding is positioned close to the magnetic core to minimize leakage inductance, while the second winding is positioned farther away to maintain isolation. The air gap and adhesive application provide localized insulation where needed, allowing optimized positioning without compromising overall isolation.
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 enhances isolation characteristics, reduces leakage inductance, and allows for more turns in windings without increasing device size, improving reliability and performance by minimizing air gaps and maintaining dielectric strength.
Implementation Method 1
a channel located in the insulating substrate and defining an opening connecting the cavity to an exterior of the insulated substrate
Implementation Method 2
first and second electrical windings that extend through the insulating substrate and around the magnetic core
Implementation Method 3
a layer of adhesive located on a floor of the cavity to secure the magnetic core in the cavity
Data Source
AI summary
A device includes a substrate including a cavity, a magnetic core in the cavity, a first winding extending around the magnetic core, and a single channel that extends between the cavity and an exterior of the device and that defines an opening. The first winding includes vias along an exterior periphery of the magnetic core opposite to the channel.