what config is this op-amp in ?

Thread Starter

haseebzaib

Joined Jun 29, 2021
8
whatopampconfig..JPG



Hello everyone. I was working on some circuit and I came across this op-amp configuration and I am confused in what configuration is this working in and what is the purpose of those diodes ?. So the purpose of this op-amp in the circuit is that it gives different voltages output depending on the input signal the output voltages varies from 0-10.6V.
 

DickCappels

Joined Aug 21, 2008
7,953
It is inverting. The diodes are there to make the gain when the input is below the 5.5V on the noninverting input voltage ten times that of when the input is above the noninverting input voltage.
 
It would certainly distort, I would not want it in my stereo system that's for certain! And the capacitor C4 is probably a small value that is rolling off high frequencies.
 
Could be used in a feedback controller where the control is asymmetric, such as anything which actively drives hard/fast in one direction, but passively returns more gentle/slowly in the other direction. Being that it's strictly proportional only however, suggests maybe it's not from a feedback circuit? Typically there's PI or PID involved, but that can also be done in another stage. Non-linear gain has many applications. For those interested in unusual non-linear op-amp circuits, here's one they never teach about in school: Easy four-quadrant multiplier using a quad op amp - EDN
 

Ramussons

Joined May 3, 2013
1,098
View attachment 245082



Hello everyone. I was working on some circuit and I came across this op-amp configuration and I am confused in what configuration is this working in and what is the purpose of those diodes ?. So the purpose of this op-amp in the circuit is that it gives different voltages output depending on the input signal the output voltages varies from 0-10.6V.
These are Proportional Integrators (PI) with Correction Clamps.
Used in Feedback Control systems to limit the Error Correction control voltages.
All control systems have a limit to the Rate of Error Control. The Rate of correction depends on the amount of Offset from the Set value. But, there is also a limit to the Rate at which corrections can be made.
The Diode-Resistor setup Reduces the Correction Rate above a certain Correction Value.
 
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