Bridge Magnetic Inductor Offset Design for Parasitic Ringing
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Solution Overview
Problem
Conventional magnetic devices in switching power converters face issues with size, efficiency, and mechanical robustness, as well as electromagnetic compatibility and parasitic ringing due to the placement of components under the inductor, which leads to increased losses and potential mechanical stress.
Innovation Solution
The use of a bridge inductor with a magnetic core offset from the substrate and a ground return conductor that serves as both a current path and a mechanical standoff, allowing components to be placed under the inductor while minimizing parasitic ringing and mechanical stress, and incorporating flexible stand-offs to accommodate substrate movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If components are placed under the inductor to minimize size, then device footprint is reduced, but parasitic ringing and electromagnetic compatibility issues increase
Solution Approach 1:
The patent moves components from the planar dimension (under the inductor on the substrate) to the vertical dimension (on top of the magnetic core), effectively utilizing the third dimension to resolve the contradiction between compact footprint and electromagnetic compatibility
Solution Approach 2:
The magnetic core serves as an intermediary structure that physically separates the inductor from substrate components while providing a mounting platform, thereby reducing parasitic coupling and electromagnetic interference between components
2Area of stationary object
If inductor is placed close to substrate to minimize size, then device footprint is reduced, but mechanical stress and reliability issues increase
Solution Approach 1:
By elevating the inductor assembly to the vertical dimension on top of the magnetic core, the design reduces mechanical stress on substrate traces and solder joints while maintaining compact overall footprint
Solution Approach 2:
The magnetic core and its mounting structure serve as a mechanical buffer that absorbs and distributes thermal and mechanical stresses, protecting the substrate and solder joints from damage before stress can propagate to critical components
3Object-generated harmful factors
If ground return conductor is added to reduce parasitic ringing, then electromagnetic compatibility improves, but device complexity increases
Solution Approach 1:
The magnetic core structure serves multiple functions simultaneously: it provides magnetic flux path for inductance, acts as a mechanical support platform for components, and serves as the mounting base for the ground return conductor, thereby reducing overall device complexity despite adding EMI protection capabilities
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 reduces substrate conductor losses, enhances mechanical robustness, and improves electromagnetic compatibility, achieving higher efficiency and smaller size while protecting components from mechanical damage.
Implementation Method 1
a magnetic core disposed over and offset from a first portion of the outer surface of the substrate
Implementation Method 2
N windings wound around at least a portion of the magnetic core
Data Source
AI summary
An electrical assembly includes a substrate, a bridge magnetic device disposed on an outer surface of the substrate, and at least one electrical component. The bridge magnetic device includes (1) a magnetic core disposed over and offset from a first portion of the outer surface of the substrate, (2) N windings wound around at least a portion of the magnetic core and electrically coupled to conductors of the substrate, where N is an integer greater than zero, and (3) a ground return conductor disposed on an outer surface of the magnetic core facing the first portion of the outer surface of the substrate. The at least one electrical component is disposed on the first portion of the outer surface of the substrate.