Sense high voltages using operational amplifiers

Hello Yassine,

The INA270 is a differential amp with -16 +80V input range.

There are other members of current sense devices that may work.

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Will these perform the function you want?

Difference_Amplifiers.pdf

Here is an app note, Published in Analog Zone.
Figure 6, page 7, shows a +-200V implementation with +-15V supply rails using a INA148.

Hello and thank you for your quick answer,

For the INA270, [-16,80]V is the common mode range not the differential input voltage.

What I need is a difference input voltage of [-20,80]V. I thought of using a voltage attenuator ( op amp + 4 resistors with a gain < 1 ) but i don't have any information about the input voltage, then i will lnot be sure that the input voltage will not exceed the op amp tolerated VCM.

I searched on differential amplifiers but no one has the [-20,80]V input range...

Thank you very much.

Hello and thank you for your quick answer,

For the schematic you sent me, there is a voltage divider that will allow us to use high voltages at the input.
The matter is that we don't have any information about the input signald ( their ground ) so we can not apply the voltage division since the grounds are different...

You must have some reference point to measure voltages.
If you could attach some schematic representation of what you are trying to do it would help finding a solution.

Hello Yassine, have you found a solution?
If not please sketch what you need to do and attach to the post.