3D Leadframe Structure for Vertical Inductor Footprint Reduction
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Solution Overview
Problem
Inductors in switching power converters occupy a large footprint, creating a trade-off between package size and performance, as they need to be undersized to fit within smaller packages, resulting in sub-optimal performance.
Innovation Solution
A three-dimensional leadframe with horizontal and vertical features is used to support and attach the inductor, reducing the overall footprint of the power converter by utilizing angled conductive winding supports and shelves, allowing for a smaller package size while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a traditional flat leadframe is used to support the inductor, then the manufacturing process is simple, but the inductor occupies a large footprint area
Solution Approach 1:
The leadframe is transformed from a two-dimensional flat structure to a three-dimensional structure by bending portions of the leadframe to form vertical conductive winding receptacles and angled support surfaces. This dimensional change allows the inductor to be supported in a vertical orientation, significantly reducing the horizontal footprint area while maintaining structural integrity and electrical connectivity.
Solution Approach 2:
The leadframe is divided into distinct functional segments: a flat circuit assembly portion, vertical conductive winding receptacles, angled conductive winding supports, and horizontal shelves. This segmentation allows each portion to perform its specific function efficiently, with the vertical receptacles reducing footprint while the shelves provide stable support for the inductor windings.
2Area of stationary object
If the inductor is undersized to fit within smaller packages, then the package size is reduced, but the performance becomes sub-optimal
Solution Approach 1:
By transitioning from a horizontal to a vertical inductor configuration, the patent enables full-sized inductors to be accommodated within smaller package footprints. The vertical orientation utilizes the third dimension (height) to house the inductor windings, allowing optimal inductor dimensions to be maintained while reducing the horizontal package area.
Solution Approach 2:
The inductor is nested within the three-dimensional leadframe structure, with the windings positioned within the vertical conductive receptacles and supported by internal shelves. This nested arrangement maximizes space utilization, allowing the inductor to maintain its optimal size and performance characteristics while being contained within a compact package footprint.
3Area of stationary object
If a three-dimensional leadframe structure is used to support the inductor, then the footprint is reduced, but the manufacturing complexity increases
Solution Approach 1:
The leadframe fabrication process is segmented into distinct stages: forming the flat circuit assembly, bending vertical portions to create receptacles, forming angled support surfaces, and creating horizontal shelves. This segmentation allows each operation to be performed independently using standard leadframe fabrication techniques, making the overall complex three-dimensional structure manufacturable through a series of simpler, sequential steps.
Data Source
AI summary
A device includes a circuit assembly and a first conductive winding support having a first end attached to the circuit assembly and having a first winding support surface a first distance from the circuit assembly. The device also includes a second conductive winding support having a second end attached to the circuit assembly and having a second winding support surface a second distance from the circuit assembly, the second distance being different than the first distance. A conductive winding has first and second winding ends. The first winding end is attached to the first winding support surface, and the second winding end is attached to the second winding support surface.