PCB焊盘布局对精密合金电阻的电压检测精度的影响

Influence of PCB Pad Layout on Voltage Detection Accuracy of Precision Alloy Resistors

电流检测电阻有多种种类可供选择,在大电流的使用环境,如汽车、功率器件等,须使用大功率的精密合金电阻。这种电阻的电阻值通常较小,通常在50 mΩ以下电阻值,电阻焊接在PCB的焊盘上时,电压的采样位置对在电流检测元件采样的精度影响较大,其结果可以大幅增加测量误差。目前通用的布局都使用4端子电阻以减少这种误差,但是不同的4端子PCB布局对电阻值的影响也不一样。本文采用一种标准的低成本4端子布局结构实现高精度开尔文检测。

There are many types of current detection resistors to choose from.In high-current use environments,such as automobiles and power devices,high-power precision alloy resistors must be used.The resistance value of this kind of resistor is usually small,usually below 50 mΩ.When the resistance is soldered on the PCB pad,the sampling position of the voltage has a greater impact on the accuracy of the current detection element sampling,and the result can greatly increase the measurement error.The current common layouts use 4-terminal resistors to reduce this error,but different 4-terminal PCB layouts have different effects on the resistance value.This article uses a standard,low-cost 4-terminal layout structure to achieve high-precision Kelvin detection.