Multi-Stage Permanent Magnet On-Chip Power Inductor
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Solution Overview
Problem
Conventional power inductors in switching power converters are large, lossy, and inefficient, limiting their inductance density and saturation current, which affects the performance of DC-DC switching power converters.
Innovation Solution
The implementation of a permanent magnet on-chip power inductor (PMOI) and permanent magnet coupled power inductor (PMCI) designs, which include a multi-stage permanent magnet structure and specific flux cancellation mechanisms to enhance saturation current and inductance density, utilizing materials like NdFeB for high residual flux density and coercivity, and employing advanced fabrication techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional power inductor structures are used, then the inductor can provide basic inductance function, but the inductance density is low and the device size is large
Solution Approach 1:
The patent changes the magnetic flux density parameter by introducing a permanent magnet that generates a DC bias flux, shifting the operating point of the magnetic core to enable higher inductance density without increasing volume. The multi-stage permanent magnet structure creates different flux densities in different regions to optimize the B-H curve operation point.
Solution Approach 2:
The patent combines ferrite magnetic core material with permanent magnet material (such as NdFeB) to create a composite magnetic structure. This composite approach leverages the high permeability of ferrite and the high residual flux density of permanent magnets to achieve superior inductance density in a compact volume.
2Reliability
If conventional power inductor structures are used, then the inductor can function, but the saturation current is limited
Solution Approach 1:
The patent applies local quality by creating a multi-stage permanent magnet structure where different stages have different dimensions and are positioned at specific locations within the magnetic core. This local differentiation optimizes the flux distribution in different regions, enabling higher saturation current by preventing localized saturation while maintaining overall structural functionality.
Solution Approach 2:
The permanent magnet is segmented into multiple stages with decreasing areas, where each stage contributes to the overall flux cancellation effect. This segmentation allows for optimized flux distribution and enables the structure to handle higher saturation currents by distributing the magnetic stress across multiple regions.
3Quantity of substance
If larger core size is used to increase inductance, then the inductance value increases, but the device weight and size increase
Solution Approach 1:
The patent changes the operating parameters of the magnetic core by introducing a permanent magnet that establishes a DC bias flux. This shifts the operating point on the B-H curve, enabling the same core volume to provide higher inductance value, thereby increasing inductance without increasing weight.
4Quantity of substance
If higher inductance density is achieved through conventional means, then the inductance per volume increases, but the saturation current and power handling capability are compromised
Solution Approach 1:
The patent changes the magnetic flux density parameter distribution by using a multi-stage permanent magnet structure. This creates an optimized B-H curve operation point that simultaneously achieves high inductance density and high saturation current, enabling the inductor to handle higher power while maintaining compact size.
Solution Approach 2:
The multi-stage permanent magnet structure creates different local flux densities in different regions of the magnetic core. This local optimization ensures that the core operates in the optimal region of the B-H curve throughout, maximizing both inductance density and power handling capability without compromising either parameter.
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 PMOI and PMCI designs significantly increase saturation current and inductance density, reducing core size and losses, thereby improving the efficiency and performance of DC-DC switching power converters while maintaining high power density.
Implementation Method 1
Permanent magnet power inductors (PMPI) utilize a permanent magnet (PM) to partially offset the flux in the magnetic core due to the DC component of the winding current
Implementation Method 2
employing a magnetic material with higher saturation flux density helps to obtain a higher saturation current
Implementation Method 3
a top ferrite layer (or magnetic core), a spiral winding layer, a permanent magnet layer, a bottom ferrite layer
Data Source
AI summary
Apparatuses and methods directed to multi-stage permanent magnet and implementations of a permanent magnet on-chip power inductor. Various circuit models, design considerations and simulation results are described. The multi-stage permanent magnet includes layers with uniform or non-uniform magnets used to control the flux distribution. The permanent magnet on-chip power converter for DC-DC switching power converters that may include a top ferrite layer, a spiral winding layer, a permanent magnet layer, a bottom ferrite layer, and a substrate layer. The permanent magnet layer may comprise a multi-stage structure wherein each stage has a decreasing area as compared to an immediate lower stage. A method of manufacturing a Permanent On-Chip Power Inductor (PMOI) is also disclosed.