EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: hal9001 on March 20, 2022, 10:44:03 am
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Is there a current sense op amp circuit to output the absolute value of the current in terms of positive volts. In other words even if current direction changes I want to know how much current is going through a current shunt but dont care about direction.
Cheers!
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You could connect 2 of the constant current outputs to the same output resistor. :)
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You need a current monitor and a simple absolute value circuit. [attach=1] Many RIRO precision opamps will work.
The current sensing method you need depends on the current, system voltage and frequency. [attach=2].
A simple method would be to use a high CMV differential amplifier (which you can home brew with loss of accuracy). This IC will work on a 120V RMS AC system[attach=3]
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You could connect 2 of the constant current outputs to the same output resistor. :)
You need a current monitor and a simple absolute value circuit. (Attachment Link) Many RIRO precision opamps will work.
The current sensing method you need depends on the current, system voltage and frequency. (Attachment Link) .
A simple method would be to use a high CMV differential amplifier (which you can home brew with loss of accuracy). This IC will work on a 120V RMS AC system (Attachment Link)
Thanks!
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You are so right.
[attachimg=1]
There are exotic and more precise expensive versions I looked at before the penny dropped.
https://www.analog.com/en/app-notes/an-105fa.htmlF (https://www.analog.com/en/app-notes/an-105fa.htmlF) (page 28) well worth a full read.
Bidirectional Absolute Value Current Sense using LTC6101 or LTC6102.
See https://www.analog.com/media/en/technical-documentation/data-sheets/ltc6101.pdf (https://www.analog.com/media/en/technical-documentation/data-sheets/ltc6101.pdf) page 18 on boosting operating voltage if you need to.
Or https://www.analog.com/media/en/technical-documentation/data-sheets/6102fe.pdf (https://www.analog.com/media/en/technical-documentation/data-sheets/6102fe.pdf)