Crank-Shaped Chip Resistor Layout for Surge Load Durability
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Solution Overview
Problem
Chip resistors with intersecting trimming grooves suffer from microcrack generation at the intersection points, leading to potential destruction under high voltage or high power loads, especially in miniaturized designs.
Innovation Solution
A chip resistor design featuring a crank-shaped resistor structure with a trimming groove that extends in an L-cut shape, separating the microcrack generation area from the main current path, thereby avoiding load concentration and enhancing surge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two trimming grooves are arranged to intersect each other to make the current path turn 180 degrees, then the entire length of the resistor is lengthened and surge characteristics are improved, but microcracks are generated at the distal ends of the trimming grooves where loads are concentrated
Solution Approach 1:
The resistor is divided into multiple segments by introducing a meandering shape with multiple turning portions instead of a single 180-degree turn. This segmentation distributes the mechanical stress and current load across multiple gentle curves, preventing concentration of loads at any single point and avoiding microcrack generation while maintaining an extended current path length for improved surge characteristics
Solution Approach 2:
The trimming grooves are designed to form gentle curved turning portions rather than sharp 180-degree angles. This curvature approach reduces stress concentration at the turns by distributing the mechanical and electrical loads smoothly across the curved path, preventing microcrack initiation while still achieving the desired current path extension for enhanced surge characteristics
2Reliability
If the entire length of the resistor is increased by forming trimming grooves, then surge characteristics are improved, but the width dimension of the resistor becomes narrower, increasing current density under large power loads
Solution Approach 1:
The resistor pattern is extended in the longitudinal dimension by introducing meandering turns rather than expanding in the width dimension. This dimensional strategy allows the current path length to be increased for improved surge characteristics while maintaining the original width dimension, thereby preserving the current-carrying capacity and power load handling capability of the resistor
Data Source
AI summary
A chip resistor 1, which is excellent in the surge characteristics and also suitable for miniaturization, is formed by printing into a crank shape, and a first area S1 surrounded by a parallelogram is a portion where a large amount of current flows while two second areas S2a, S2b located outside the first area S1 are portions with small current distributions. A trimming groove 12 for adjustment of a resistance value is formed into an L-cut shape as a whole such that it has a coarse adjustment portion 12a formed to pass through the second area S2a and extend into the first area S1 and a fine adjustment portion 12b formed to pass through the first area S1 from the distal end of the coarse adjustment portion 12a and extend to a position reaching the second area S2a again.