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I'm trying to build a 20A E load and decided to use a 0.01Ohm shunt for the current measurements and set so I needed to amplify the shunt voltage by 10 using the "rail to rail" AD4522-2.

At 0A on RShunt I get 0.17V at the output and that doesn't change until after roughly 1A RShunt which is a dead band of 5% for me which I suppose is because of the rail limitations of the amplifier.

What is the common solution to offset up (add 0.2V to thrbop amp output) of the amplifier / shunt input so I will be able to measure the full current range of my shunt from 0-20A?

Note current sensing op amp U3 has 3.3V connected to VCC

Schematic below:

E-Load_sens

Also I'd love to hear improvement suggestions for the circuit.

JRE
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MikeLemo
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    You haven't shown a circuit so how can anyone offer improvements. Show all power detail and resistors and decoupling capacitors. Do it before the question gets closed down. – Andy aka Dec 30 '20 at 11:09
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    Then, when you've done adding the schematic, please review your earlier 9 questions to see which answers can be formally accepted (by you) following these guidelines: [Take the tour](https://electronics.stackexchange.com/tour). Of course if you are one of those folk who think they don't need to reward good work then, don't bother doing what is expected from you on this site. You might want to consider your actions on other parts of SE also. Nobody wants to see you acquiring a reputation of being mean. – Andy aka Dec 30 '20 at 11:15
  • Yeah well looks like the schematic slipped through and I'm flexible with the solution as I see that the question might have a few approches to it through different parts of the circuit to just properly measure the current and get the correct output without loosing that dead voltage band due to offset. Also It might be a better solution to just offset the GND supply around -0.2V to access the whole current range reading from the op amps output... – MikeLemo Dec 30 '20 at 20:54

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