求助大佬，低测电流检测

dadadarouqiuang

电流检测中，用的是低测电流检测，从采样电阻两端引出两根线，输入放大器，其中有一根是接地的线，那这两根线还需要走差分么，如果需要的话，其中有一根地线怎么走差分？
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超級狗

踢哀（TI）Current Sense Shunt Resistor Layout Considerations

fuu65iwi

你调换一下运放的同相输入端和反相输入端与采样电阻的连接位置（互换）。单电源（正电源）运放搭成的差分放大电路工作时，必须输入负的差分信号（即反相输入端的电压高于同相输入端）电路才能工作正常。  

超級狗

Low Side Current Sense Circuit
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超級狗

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fuu65iwi 发表于 2023-2-13 18:25
你调换一下运放的同相输入端和反相输入端与采样电阻的连接位置（互换）。单电源（正电源）运放搭成的差分放 ...

Figure 1 is a simple two pad approach, but note that the sense lines are taken from the inner center of the chip. The high currents flowing on the sides of the connection are balanced, allowing a good measurement of VSENSE + and VSENSE - . This type of layout is simple to route and is easy to assemble on a PCB. This layout is recommended for designs where the value of RSENSE is relatively large compared to RSOLDER (100:1).
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Figure 2 is typically the best layout for accuracy as the sense lines route to the inner center of the chip and uses four pad sensing. The drawback to this approach is that the pads have a higher risk of getting shorted in assembly. If this occurs, you may not see the short since the resistor can be covering the pads; this would result in a two pad sense.

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Figure 3 is another four pad sense layout, but the sense pads are at the bottom. This layout is easier to assemble than Figure 2 and you can easily see if there are any shorts between the pads.
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155351394

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