Cross-Wound Multi-Winding Inductor for Negative Coupling in VRMs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The design of voltage regulation modules (VRMs) faces challenges in achieving high power density, efficiency, and dynamic performance due to the volume of multi-winding inductors, which also hinders heat dissipation, and the lack of negative coupling inductors complicates meeting these requirements.
Innovation Solution
A multi-winding inductor design with a magnetic core and windings arranged crosswise, featuring notches or holes for overlapping portions, and varying air gaps to adjust magnetic reluctance, along with conductive elements for efficient power and signal connections, enhances negative coupling and reduces impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the volume of multi-winding inductor is increased to meet inductance requirements, then the inductance amount and efficiency are improved, but the power density and heat dissipation capability deteriorate
Solution Approach 1:
The patent transitions from traditional planar winding layouts to a three-dimensional stacked configuration with windings arranged on opposite sides of the magnetic core. This vertical stacking approach increases the effective winding area without expanding the horizontal footprint, thereby improving inductance and efficiency while maintaining compact power density
Solution Approach 2:
Multiple windings are nested within a compact magnetic core structure, with each winding positioned in a specific spatial relationship to maximize magnetic coupling. The windings are arranged in a nested configuration where inner windings are surrounded by outer windings, optimizing the use of available space while achieving required inductance values
2Temperature
If the switching unit is arranged over the multi-winding inductor to maximize heat dissipation, then the heat dissipation capability is improved, but the inductor cannot achieve negative coupling
Solution Approach 1:
The patent introduces asymmetric air gap configurations where different air gaps are provided in different magnetic paths. Specifically, the first air gap in the first magnetic path has a different length than the second air gap in the second magnetic path, creating unequal magnetic reluctances that enable negative coupling while maintaining thermal performance
Solution Approach 2:
Different regions of the magnetic core are designed with different properties - some regions have air gaps while others have direct magnetic paths. The air gaps are strategically positioned in specific magnetic columns to create the desired negative coupling effect in certain paths while maintaining overall magnetic efficiency and heat dissipation
3Ease of manufacture
If equal air gaps are provided in all magnetic paths, then the manufacturing simplicity is maintained, but the negative coupling cannot be achieved
Solution Approach 1:
Instead of uniform air gaps throughout, the patent applies local quality by providing different air gap lengths in specific magnetic paths. The first magnetic path has a first air gap while the second magnetic path has a second air gap of different length, creating the asymmetry needed for negative coupling while maintaining manufacturability through standardized gap formation processes
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 design improves efficiency and dynamic performance by minimizing impedance and providing sufficient space for connections, thus optimizing power density and heat dissipation in VRMs.
Implementation Method 1
a first magnetic path including the first cover plate, the first magnetic column, the second cover plate and the third magnetic column; a second magnetic path including the first cover plate, the second magnetic column, the second cover plate and the fourth magnetic column
Implementation Method 2
a first air gap is provided in the first magnetic column and the third magnetic column; a second air gap is provided in the second magnetic column and the fourth magnetic column
Data Source
AI summary
A multi-winding inductor includes a magnetic core including four magnetic columns and a winding assembly including two windings. Each winding includes three portions. The first and third portions of the first winding are respectively between the first and the second magnetic columns, and the third and the fourth magnetic columns; and the first and third portions of the second winding are respectively between the fourth and the first magnetic columns, and the second and the third magnetic columns. Both the first portions of two windings extend to a surface of the magnetic core and respectively form a first and a third pins. The winding is a flat wire with the thickness less than the width, and the width direction is parallel to an extension direction of the first magnetic column.