Planar Transformer PCB Winding Layout for Lower Resistance
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Solution Overview
Problem
Existing power converters in portable electronic devices face challenges in achieving slim, light, energy-efficient, and cost-effective designs due to the complexity of traditional transformer structures, which hinder advancements in power efficiency and fabrication costs.
Innovation Solution
A planar transformer assembly with a magnetic core and PCB windings configured in a PSS structure, utilizing a single shielding layer and air gaps to optimize winding arrangements, reducing resistance and enhancing current uniformity, while employing a 6-layer or 8-layer PCB for efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional transformer structures are used, then power conversion function is achieved, but device complexity and fabrication cost increase
Solution Approach 1:
The transformer is segmented into modular components including a magnetic core with multiple pillars, primary and secondary windings distributed across different PCB layers, and divided shielding layers. Each segment can be independently designed and manufactured, then assembled into the complete transformer structure, reducing overall complexity and fabrication cost.
Solution Approach 2:
The patent transitions from traditional planar or toroidal transformer geometries to a three-dimensional structure where windings are distributed across multiple PCB layers (6-layer or 8-layer configurations). This dimensional approach allows optimized magnetic coupling and electrical isolation while maintaining a compact footprint.
2Loss of energy
If PCB layers are increased to 6 or 8 layers, then energy transfer efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The multi-layer PCB serves multiple functions simultaneously: it provides electrical connectivity for primary and secondary windings, magnetic coupling paths through adjacent layers, mechanical support for the transformer structure, and electromagnetic shielding through dedicated ground layers. This consolidation of functions improves energy transfer efficiency while managing manufacturing complexity.
Solution Approach 2:
The transformer structure employs nested layering where inner layers contain primary windings and adjacent outer layers contain secondary windings, with ground and power layers nested between them. This nested configuration optimizes magnetic coupling and minimizes parasitic effects, enhancing energy transfer efficiency.
3Reliability
If air gaps are introduced in magnetic core, then magnetic flux distribution improves, but manufacturing precision requirements increase
Solution Approach 1:
Air gaps are strategically introduced at specific locations within the magnetic core structure, particularly at the junctions of magnetic pillars, to locally control magnetic flux distribution. This localized approach prevents core saturation and reduces magnetic losses without requiring high precision across the entire core assembly.
Solution Approach 2:
The magnetic core design incorporates adjustable air gap parameters including gap size, position, and distribution. By optimizing these parameters during design, the transformer achieves improved magnetic flux distribution and reduced core losses while maintaining manufacturability through standard fabrication tolerances.
4Ease of manufacture
If shielding layers are reduced to single layer, then fabrication cost decreases, but electromagnetic interference increases
Solution Approach 1:
A single continuous shielding layer is positioned between primary and secondary windings to act as an electromagnetic intermediary. This shielding layer, connected to ground, intercepts and redirects electromagnetic fields, reducing interference between primary and secondary circuits while maintaining cost-effective single-layer construction.
Solution Approach 2:
The shielding function is merged with the PCB ground layer structure, where continuous ground planes on specific PCB layers serve dual purposes as both electrical reference and electromagnetic shielding. This integration eliminates the need for separate shielding materials while maintaining EMI protection.
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
The planar transformer assembly achieves reduced DC resistance, uniform current flow, and lower fabrication costs, aligning with the goals of slim, energy-efficient, and cost-effective designs for modern electronic devices.
Implementation Method 1
A planar transformer assembly with a magnetic core and PCB windings configured in a PSS structure, utilizing a single shielding layer and air gaps to optimize winding arrangements
Data Source
AI summary
A planar transformer assembly and a power adapter are provided. The planar transformer assembly includes a first printed circuit board (PCB). The first PCB includes a magnetic core, a first primary PCB winding, a first secondary PCB winding and a second secondary PCB winding. The magnetic core passing through the first PCB includes a first cover plate, a second cover plate, and a first magnetic pillar. The first magnetic pillar is connected to the first cover plate. The first magnetic pillar is separated from the second cover plate by a first air gap. The first primary PCB winding is wrapped around a first portion of the first magnetic pillar. The first secondary PCB winding and the second secondary PCB winding are wrapped around a second portion of the first magnetic pillar below the first portion. The second portion is a single portion of the first magnetic pillar.