I am designing a current sensing application on a solar PV line. The line voltage will be around 1500V DC. Since we are planning to measure the current on the low side
1. Can the current sense amplifier be connected to the shunt directly?
2. Should I consider any other additional design constraints?
Hello,
1, Below is a picture demonstrating how to connect an INA for low-side current sensing. The picture below is only to show how to connect the Rshunt/Rsense to the INA.
2, I would need to know more about the application in order to understand what is important but for the most part accuracy will pose the most constraints. Since you are sensing on the low side making sure the common mode voltage does not go below the min Vcm of the INA210 is important.
If you have any other questions please reply
Regards,
Castrense
Hello,
You can do low side sensing as shown in the image but as Kai mentioned you will have all the problems associated with low side sensing. Here is a link that speaks about high-side vs low-side sensing: https://e2e.ti.com/blogs_/b/analogwire/posts/system-trade-offs-for-high-and-low-side-current-measurements
As far as the accuracy there are a range of factors that will influence the accuracy. I have attached a screenshot of a tool on the product page of current sense amplifiers that will calculate the % error for each specific device.
Pictured above is the error analysis for the INA181 found by scrolling down on the INA181's product page. Using the TI store current sense amplifier parametric search you can find the device you want and on its product page use the error analysis to help design for your spec.
I was also alerted to special isolated amplifiers that can handle the 1500V known as the AMC devices. https://www.ti.com/isolation/isolated-amplifiers/products.html
Regards,
Castrense
