Slit Resistor Layout for Low TCR Current Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing resistors with metal plate resistive elements experience increased temperature coefficient of resistance (TCR) when slits are used to adjust resistance, leading to reduced accuracy in current detection due to heat-generated resistance variations.
Innovation Solution
A resistor design featuring a resistive element with slits, a protective film, and electrodes, where the protective film's edges are strategically positioned relative to the slits, and includes insulating and intermediate layers to enhance bonding and heat dissipation, reducing TCR variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a slit is provided near either one of the pair of electrodes to adjust the resistance value, then the resistance value can be adjusted, but the temperature coefficient of resistance increases
Solution Approach 1:
The resistive element is divided into multiple segments by providing both a first slit and a second slit, rather than a single slit. This segmentation allows for better distribution of thermal stress and reduces the overall temperature coefficient of resistance while still achieving the desired resistance value adjustment.
Solution Approach 2:
The patent applies different structural characteristics to different regions of the resistive element. The first slit is positioned closer to the first electrode and the second slit closer to the second electrode, creating asymmetric local structures that optimize both resistance adjustment and thermal performance in different zones.
2Measurement precision
If the resistance value is reduced to improve current detection accuracy, then detection accuracy improves, but the temperature coefficient of resistance increases
Solution Approach 1:
By providing multiple slits (first and second slits) in the resistive element, the patent achieves low resistance values necessary for accurate current detection while the segmented structure reduces thermal effects that would otherwise increase the temperature coefficient of resistance.
Solution Approach 2:
The asymmetric positioning of the first and second slits relative to the electrodes creates a resistance distribution that optimizes both the overall resistance value and thermal performance, allowing low resistance for accurate detection while maintaining stability.
3Ease of operation
If heat is generated from the resistive element during use, then current detection function is performed, but the resistance value varies due to increased temperature coefficient of resistance
Solution Approach 1:
The resistive element is segmented by first and second slits that extend in the thickness direction, creating multiple thermal zones that reduce overall temperature rise and stabilize resistance value during current detection operation.
Solution Approach 2:
The slits extend in the thickness direction of the resistive element, utilizing the Z-dimension to create thermal management pathways that stabilize resistance during operation while maintaining the planar current detection function.
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 effectively suppresses the increase in temperature coefficient of resistance, improving accuracy and heat dissipation while maintaining consistent resistance values.
Implementation Method 1
a protective film disposed on the first surface and having electrical insulating properties
Implementation Method 2
suppresses an increase of the temperature coefficient of resistance... variation increases in the resistance value of the resistor caused by heat generated from the resistive element
Data Source
AI summary
A resistor includes a resistive element including a first surface and a second surface facing opposite sides in a thickness direction; a protective film having electrical insulating properties disposed on the first surface; and a pair of electrodes disposed spaced apart from each other in a first direction perpendicular to the thickness direction, the pair of electrodes being configured to come into contact with the resistive element. The protective film includes a first outer edge and a second outer edge spaced apart from each other in the first direction and extending in a second direction perpendicular to both the thickness direction and the first direction. The resistive element includes a first slit and a second slit extending from the first surface through to the second surface and extending in the second direction. The first slit is located closest to the first outer edge; and the second slit is located closest to the second outer edge. As viewed in the thickness direction, a first distance from the first outer edge to the first slit and a second distance from the second outer edge to the second slit together have a length 15% or greater of a dimension of the protective film in the first direction.