Lead Frame Power Inductor Design for Compact Packaging
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Solution Overview
Problem
Existing discrete inductors face challenges in manufacturing efficiency, cost-effectiveness, maximizing inductance per unit area, minimizing resistance, and achieving a compact size with a small footprint, particularly in high-volume production.
Innovation Solution
A discrete power inductor design featuring top and bottom lead frames that form a coil around a single closed-loop magnetic core, with non-linear, stepped configurations for lead connections and the use of conductive vias for interconnections, allowing for efficient magnetic coupling and compact packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wire wound inductors are used, then inductance can be achieved, but manufacturing complexity and production inefficiency increase
Solution Approach 1:
The patent replaces the traditional mechanical wire winding process with a planar lead frame configuration where conductive traces are deposited and patterned on a substrate. This substitution eliminates complex winding machinery and manual operations, enabling high-volume automated manufacturing while maintaining inductance functionality through controlled trace geometry and magnetic core integration.
Solution Approach 2:
The invention transitions from three-dimensional wire winding to a two-dimensional planar structure. The lead frame with its patterned conductive traces on a flat substrate allows inductance to be achieved through planar geometry rather than volumetric winding, simplifying manufacturing and enabling compact integration while maintaining electrical functionality.
2Quantity of substance
If multiple layers are used to increase inductance, then inductance per unit area improves, but structural complexity and manufacturability worsen
Solution Approach 1:
The patent combines the magnetic core and conductive traces into a single integrated planar structure. The magnetic core is positioned beneath the lead frame, and the conductive traces are directly patterned on the substrate, merging what would traditionally be separate components into one manufacturable unit. This integration achieves high inductance density without requiring multiple stacked layers.
Solution Approach 2:
The lead frame is divided into multiple conductive trace segments that are strategically positioned and connected on the planar substrate. By segmenting the conductive path into optimized trace sections with varying geometries and positions, the design achieves high inductance per unit area through careful layout rather than through vertical stacking of multiple layers.
3Volume of moving object
If compact size is achieved, then footprint and profile are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The lead frame structure incorporates self-aligning features and standardized geometries that automatically position components correctly during assembly. The planar configuration with defined trace patterns and magnetic core positioning allows the structure to self-correct minor variations, reducing the stringency of manufacturing precision requirements while maintaining compact dimensions.
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 achieves high inductance per unit area, minimizes resistance, and provides a compact, cost-effective, and easily manufacturable power inductor suitable for high-volume production, particularly in applications like DC-DC power converters.
Implementation Method 1
the interconnected leads of which form a coil about a closed-loop magnetic core
Implementation Method 2
a coil about a closed-loop magnetic core
Data Source
AI summary
A lead frame-based discrete power inductor is disclosed. The power inductor includes top and bottom lead frames, the leads of which form a coil around a single closed-loop magnetic core. The coil includes interconnections between inner and outer contact sections of the top and bottom lead frames, the magnetic core being sandwiched between the top and bottom lead frames. Ones of the leads of the top and bottom lead frames have a generally non-linear, stepped configuration such that the leads of the top lead frame couple adjacent leads of the bottom lead frame about the magnetic core to form the coil.