Current sensing: What is the difference between using high-side sensing and low-side sensing?

dianhang

Current sensing: What is the difference between using high-side sensing and low-side sensing? [Copy link]

I would like to ask about current detection: What is the difference between high-end detection and low-end detection? Are there any disadvantages? What should I pay attention to respectively?

hpzax

The principle of high-end detection and low-end detection is the same. In fact, from the perspective of cost, chip usage requirements and technology, low-end detection has low cost and low chip requirements. High-end detection requires high chip common mode voltage. Such chips are rare. Even if they are available, they are expensive. Low-end detection does not require high chip common mode voltage, and the chip price is low.

alan000345

hpzax posted on 2018-11-9 14:54 The principles of high-end detection and low-end detection are the same. In fact, from the perspective of cost, chip usage requirements and technology, low-end detection has low cost and high requirements for chips...

Very good introduction, good.

hpzax

Simply put, high-end detection generally means that the current sampling end is at the positive pole of the power supply, and the low-end sampling sampling resistor is at the negative pole of the power supply. For high-end sampling, the input and output are grounded together, and other signals are easy to process. The disadvantage is that the circuit is complicated and the chip requirements are high; low-end sampling input and output are grounded together, the chip cost is low, and the measurement is easily disturbed. Low-end sampling input and output are not grounded together. The disadvantage is that there is a sampling resistor between the input and output. The advantage is simplicity. Of course, if you use a Hall current sensor, there will be no high-end and low-end problems, but the disadvantages are that the accuracy is not enough and the price is high.

qwqwqw2088

It depends on the accuracy of current measurement. High-end circuits are generally more complicated.

陈ZX

If it is a fixed part of the device, high-side detection is still much more difficult than low-side detection. But if it is used as an instrument to detect high and low sides, as long as a battery-powered detector or amplifier plus a multimeter,

This can detect currents from nA to several A. It is quite precise and you can take a look at it.

Ke'er has a precision current detector.

https://item.taobao.com/item.htm?spm=a2oq0.12575281.0.0.25911debTYlnGV&ft=t&id=609891309368

It can detect currents from nA to 1A, using batteries, a research and development artifact. Because it uses batteries, the detector ground is suspended, and both high-side and low-side currents can be detected. It can also amplify uV and millivolt voltages, with an amplification factor of 100. It is mainly used for research and development, testing, and other detection purposes, and is very precise and reliable. Also QQ962656871