Embedded Magnetic Component Isolation via Cavity Obstruction
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Solution Overview
Problem
Existing embedded magnetic components face challenges in achieving high isolation performance due to limitations in dielectric strength, leading to increased size and potential contamination issues, which affect safety agency approvals and product miniaturization.
Innovation Solution
A method involving a magnetic core embedded in a cavity within an insulating substrate with a channel obstruction to contain adhesive, maintaining an air gap and using additional insulating layers to reduce spacing between windings, enhancing isolation without fully encapsulating the core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy gel is used to fill the cavity and fully cover the magnetic component, then the magnetic component is securely embedded and isolated, but air bubbles form in the epoxy gel during solidification which can expand during reflow soldering and cause device failure
Solution Approach 1:
The patent removes the epoxy gel filling step entirely, extracting the harmful element (epoxy gel that traps air bubbles) from the system. Instead, the magnetic component is embedded in a cavity with air gaps maintained around it, eliminating the source of bubble-related reliability issues while still achieving secure embedding through mechanical fitting and adhesive application to the cavity floor
Solution Approach 2:
The patent creates an inert air environment around the magnetic component by maintaining air gaps instead of filling with epoxy gel. This inert atmosphere prevents the formation of harmful air bubbles during processing while still providing adequate isolation when combined with insulating layers and adhesive containment
2Reliability
If larger spacing is provided between primary and secondary windings to achieve high isolation, then isolation performance improves, but the device size increases and miniaturization becomes difficult
Solution Approach 1:
The patent changes the dielectric parameter by introducing solid insulating layers (PCB substrate material) between the windings instead of relying on air spacing. This parameter change allows the isolation distance to be reduced significantly while maintaining high breakdown voltage, enabling miniaturization without sacrificing isolation performance
Solution Approach 2:
The patent uses composite insulation structure combining the PCB substrate material (fiberglass epoxy) as insulating layers between windings. This composite approach provides superior dielectric strength compared to air gaps, allowing reduced spacing while achieving the required isolation performance for safety approvals
3Stability of the object's composition
If adhesive is applied freely in the cavity to secure the magnetic core, then the magnetic core is firmly fixed, but adhesive may leak through the channel to the outside of the component
Solution Approach 1:
The patent segments the cavity space by introducing a channel obstruction portion that divides the cavity into an adhesive application region and a magnetic component placement region. This segmentation allows adhesive to be contained in the first region where it secures the magnetic core without leaking through the channel to the exterior
Solution Approach 2:
The channel obstruction portion acts as an intermediary barrier between the adhesive and the channel. It prevents direct contact and potential leakage of adhesive through the channel while still allowing the adhesive to perform its function of securing the magnetic core in place
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 approach significantly reduces the isolation distance required, allowing for smaller component designs while maintaining high isolation performance and safety standards, reducing the risk of arcing and component failure.
Implementation Method 1
a layer of adhesive on the cavity floor, wherein the magnetic core is secured in the cavity by the layer of adhesive
Data Source
AI summary
In manufacturing an embedded magnetic component, a cavity is formed in an insulating substrate with one or more channels connecting the cavity to an exterior of the component. The channels include one or more obstruction sections that define a sealed base area of the cavity into which adhesive is dispensed to secure the magnetic core in the cavity. The obstruction sections prevent egress of the adhesive before it hardens. The cavity and the magnetic core are then covered with a first insulating layer. Through holes are formed through the first insulating layer and the insulating substrate, and plated up to form conductive vias. Metallic traces are added to the exterior surfaces of the first insulating layer and the insulating substrate to form upper and lower winding layers. The metallic traces and the conductive vias form the windings for an embedded magnetic component, such as a transformer or an inductor.