Embedded Transformer Resin Isolation for 0.4 Mm Winding Spacing
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Solution Overview
Problem
Existing embedded magnetic component devices face challenges in achieving high isolation performance due to the limited dielectric strength of air, which requires large spacing between primary and secondary windings, thereby increasing device size and potentially leading to issues like air bubble formation and contamination affecting isolation.
Innovation Solution
The implementation of a device with a magnetic core made of ferrite and an insulating substrate with a cavity housing the magnetic core, featuring primary and secondary electrical windings with a reduced spacing between them, and the use of first and second isolation barriers made of resin material to enhance electrical insulation and reduce the risk of arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If air is used as the insulating medium between primary and secondary windings, then the device structure is simple, but the isolation performance is poor requiring large spacing between windings
Solution Approach 1:
A resin layer is introduced as an intermediary insulating medium between the primary and secondary windings, replacing air as the dielectric material. This resin layer has superior dielectric strength compared to air, enabling adequate electrical isolation with reduced spacing between windings, thus resolving the contradiction between structural simplicity and isolation performance.
Solution Approach 2:
The dielectric material parameter is changed from air to resin, which has higher dielectric strength. This parameter change allows the spacing between primary and secondary windings to be reduced while maintaining or improving isolation performance, effectively resolving the technical contradiction.
2Reliability
If large spacing is provided between primary and secondary windings to ensure isolation, then isolation performance is improved, but device size increases
Solution Approach 1:
The dielectric material is changed from air to resin with higher dielectric strength, allowing the spacing between windings to be reduced. This parameter change enables compact device design while maintaining adequate isolation performance, resolving the contradiction between isolation performance and device size.
Solution Approach 2:
The patent uses a composite structure where resin material is applied as an insulating layer between windings. This composite approach (resin + air comparison) leverages the superior dielectric properties of resin to achieve compact dimensions without compromising isolation performance.
3Ease of manufacture
If epoxy gel is used to fill the cavity during manufacturing, then the magnetic component is fully covered, but air bubbles form and expand during reflow soldering causing device failure
Solution Approach 1:
The epoxy gel filling step is removed from the manufacturing process. Instead of filling the cavity with epoxy gel, the patent leaves it empty or fills it with air, eliminating the source of air bubble formation and expansion during reflow soldering, thus preventing device failure while still achieving adequate coverage and protection.
Solution Approach 2:
The potential harm of air bubbles forming in epoxy gel during reflow soldering is converted into a benefit by simply not using epoxy gel filling. The air space, which would otherwise cause problems, is accepted as the filling medium, eliminating the air bubble expansion issue entirely while maintaining structural integrity through the resin isolation layers.
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 significantly improves isolation characteristics by reducing the required spacing between primary and secondary windings to 0.4 mm, allowing for more compact device designs while maintaining high insulation integrity.
Implementation Method 1
first and second isolation barriers made of resin material to enhance electrical insulation and reduce the risk of arcing
Data Source
AI summary
An embedded magnetic component device includes a magnetic core located in a cavity extending into an insulating substrate. The cavity and magnetic core are coved with a cover layer. Through holes extend through the cover layer and the insulating substrate, and are plated to define conductive vias. Metallic traces are provided at exterior surfaces of the cover layer and the insulating substrate to define upper and lower winding layers. The metallic traces and conductive vias define the respective primary and secondary side windings for an embedded transformer. At least a first isolation barrier is provided on the cover layer, and at least a third insulating layer is provided on the substrate. The second and third insulating layers provide additional insulation for the device, and define and function as a circuit board for surface mounted power electronics.