PCB Planar Transformer Layout for High-Density Isolated Converters
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Solution Overview
Problem
Traditional transformers in isolation converters have low power density due to their large size, which limits miniaturization and increases volume, making it difficult to achieve high efficiency and compact design.
Innovation Solution
A planar transformer is used in isolation converters, where primary-side and secondary-side coils are formed as traces on a circuit board, surrounded by an iron core with an air gap, allowing for increased space utilization and higher operating frequency, enabling smaller size, higher efficiency, and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional transformers are used in isolation converters, then the transformer structure is simple and easy to manufacture, but the transformer size is large and power density is low
Solution Approach 1:
The patent transitions from traditional three-dimensional wound coil structures to a planar two-dimensional trace structure on a circuit board. The primary and secondary coils are formed as planar traces on different layers of the circuit board, with the iron core positioned between them. This dimensional change from 3D winding to 2D planar layout significantly reduces the transformer's volume while maintaining electrical functionality, directly resolving the contradiction between ease of manufacture and transformer size.
2Ease of manufacture
If traditional transformers are used in isolation converters, then the manufacturing process is conventional and simple, but the operating frequency is low and efficiency is limited
Solution Approach 1:
The patent changes the physical parameters of the transformer structure by adopting planar traces with optimized width, spacing, and layer configuration. The trace width and spacing are carefully designed to achieve optimal electrical characteristics for high-frequency operation. Additionally, the iron core with air gap is positioned close to the traces, enhancing magnetic coupling efficiency. These parameter changes enable the transformer to operate at higher frequencies while maintaining manufacturing simplicity through standard PCB fabrication processes.
3Reliability
If traditional transformers are used, then the structure is conventional and reliable, but the power density is low and miniaturization is difficult
Solution Approach 1:
The patent merges the transformer structure with the circuit board by forming the primary and secondary coils as traces directly on the PCB layers. The iron core is positioned between the trace layers, creating an integrated assembly where the circuit board serves as both the structural support and the electrical conductor carrier. This merging eliminates the need for separate winding frames and coil assemblies, significantly reducing the overall transformer volume while maintaining structural reliability through the rigid PCB substrate.
4Stability of the object's composition
If traditional transformers are used in isolation converters, then the design is conventional and stable, but the converter size is large and heat dissipation is poor
Solution Approach 1:
The planar configuration spreads the copper traces across large areas of the circuit board, creating extended heat dissipation surfaces. The traces on both sides of the board can be connected to thermal vias and ground planes that conduct heat away from the transformer core. This two-dimensional heat distribution path is more effective than the concentrated heat paths in traditional 3D wound transformers, enabling better thermal management while maintaining design stability.
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 design significantly increases power density, reduces power switch size, and enhances efficiency, weight reduction, and heat dissipation performance in isolation converters.
Implementation Method 1
The primary-side trace serves as a primary-side coil coupled to the primary-side circuit. The secondary-side trace serves as a secondary-side coil coupled to the secondary-side circuit. The iron core includes a core pillar, and the core pillar penetrates a through hole of the circuit board, and the primary-side trace and the secondary-side trace surround the through hole.
Implementation Method 2
The iron core includes a core pillar, and the core pillar penetrates a through hole of the circuit board, and the primary-side trace and the secondary-side trace surround the through hole.
Data Source
AI summary
A planar transformer is applied to an isolated converter, and the isolated converter includes a primary-side circuit and a secondary-side circuit. The planar transformer includes a circuit board and an iron core, and the circuit board includes a primary-side layer and a secondary-side layer. The circuit board is arranged in the isolated converter, and the primary-side layer and the secondary-side layer include a primary-side trace and a secondary-side trace respectively. The primary-side trace is formed on the primary-side layer and serves as a primary-side coil coupled to the primary-side circuit. The secondary-side trace is formed on the secondary-side layer and serves as a secondary-side coil coupled to the secondary-side circuit. The iron core includes a core pillar, the core pillar penetrates through a through hole of the circuit board, and the primary-side trace and the secondary-side trace surround the through hole.