Planar PCB Switching Power Supply With Magnetic Sheet Shielding
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Solution Overview
Problem
Existing switching power supply devices face limitations in reducing thickness, managing heat dissipation, and productivity due to the use of embedded magnetic cores and multilayer inductor arrays, which also result in unwanted radiation and increased production complexity.
Innovation Solution
A switching power supply device with a multilayer printed board featuring a planar array winding configuration, utilizing a soft magnetic sheet on both sides of the board to form a magnetic layer, which reduces unwanted radiation and simplifies the winding structure, allowing for compact design and improved productivity by eliminating the need for individual magnetic cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If embedded magnetic cores are used in multilayer boards, then inductance is achieved, but the thickness of the device is restricted by the magnetic core thickness
Solution Approach 1:
The patent extracts the magnetic core from the traditional embedded position within the multilayer board and relocates it to the outer surface of the board. This allows the conductor patterns to form inductors without requiring thick embedded magnetic cores, thereby reducing the overall device thickness while maintaining inductance functionality.
Solution Approach 2:
The patent transitions from a three-dimensional embedded magnetic core structure to a two-dimensional planar inductor structure where conductor patterns are formed on the board surface. This dimensional change eliminates the thickness constraint imposed by embedded magnetic cores while achieving the required inductance through planar winding patterns.
2Temperature
If individual magnetic cores are used for each inductor, then inductance is achieved, but heat dissipation area is small causing heat concentration
Solution Approach 1:
The patent merges multiple individual magnetic cores into a single shared magnetic core structure. Multiple inductors share common magnetic path and core material, which increases the effective heat dissipation area and distributes heat generation across a larger region, preventing heat concentration while maintaining individual inductor functionality.
Solution Approach 2:
The shared magnetic core serves multiple functions: it provides magnetic path for multiple inductors simultaneously, acts as a common heat dissipation structure, and enables magnetic coupling between inductors. This multi-functionality resolves the heat dissipation issue while simplifying the overall structure.
3Productivity
If air-core inductor array is used, then productivity is improved, but unwanted magnetic field radiation occurs
Solution Approach 1:
The patent introduces a magnetic shielding layer as an intermediary between the air-core inductor array and the external environment. This shielding layer effectively blocks unwanted magnetic field radiation while allowing the air-core structure to maintain its manufacturing advantages, thus resolving the contradiction between productivity and electromagnetic compatibility.
4Adaptability or versatility
If multiple product line-ups are created for different specifications, then electric power requirements are met, but production and manufacturing management become complicated
Solution Approach 1:
The patent designs a universal inductor structure with standardized conductor patterns and shared magnetic cores that can accommodate different inductance values and current ratings through parameter adjustments rather than structural changes. This universal design allows a single product platform to serve multiple specifications, eliminating the need for multiple product line-ups and simplifying production and manufacturing management.
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 solution achieves a compact, thin switching power supply device with effective heat dissipation and reduced radiation, enhancing productivity and cost efficiency by using a soft magnetic sheet as a magnetic path for the windings, thereby simplifying the structure and reducing production complexity.
Implementation Method 1
magnetic flux generated by current flowing to the plurality of windings
Implementation Method 2
the magnetic sheet being made of a soft magnetic body forming a magnetic layer
Implementation Method 3
heat generation and increase in temperature
Data Source
AI summary
A switching power supply device includes a power conversion circuit that is provided at a multilayer printed board and includes a plurality of switching circuits and a controller controlling the switching circuits, windings configuring an inductor at the multilayer printed board, and a magnetic sheet on one or both of upper and lower faces of the multilayer printed board. First ends of the windings are connected to the switching circuits, and second ends of the windings are connected to a common output. The controller controls the plurality of switching circuits to periodically vary a position and a time at which magnetic flux generated by current flowing to the windings reaches the maximum magnetic flux density. Thus, the switching power supply device is thin, achieves dispersion of heat generation, handles variations in the magnitude of electric power by varying the area of the board, and effectively reduces unwanted radiation.