Hi everyone,

Adding to the discussion, I'd like to share the problems I am facing using this IC model. I also followed the application note trying to implement what was suggested by Vishay, but the results were similar to some of the problems described previously. In the image attached, the first output implements the positive Unipolar Photovoltaic Amplifier (UPA), the second output implements the negative UPA and in the third, I use an ideal OpAmp instead of the TL082 for the negative UPA. As you can see in the results, when the system uses a model of a real OpAmp the output current of this elements stay in an expected order of magnitude, but the output voltage don't follow the input. With the ideal OpAmp, the model reproduces the exactly same voltage of the input (the distortion on the top was already there), but the current goes higher then 5A.

I don't have a solution to this yet, but I hope you can see things I don't.



Moderation: created your own thread.
Link to other thread
https://forum.allaboutcircuits.com/threads/il300-optocoupler-simulation-problem.209198/post-2016156

 

Hi everyone,

Adding to the discussion, I'd like to share the problems I am facing using this IC model. I also followed the application note trying to implement what was suggested by Vishay, but the results were similar to some of the problems described previously. In the image attached, the first output implements the positive Unipolar Photovoltaic Amplifier (UPA), the second output implements the negative UPA and in the third, I use an ideal OpAmp instead of the TL082 for the negative UPA. As you can see in the results, when the system uses a model of a real OpAmp the output current of this elements stay in an expected order of magnitude, but the output voltage don't follow the input. With the ideal OpAmp, the model reproduces the exactly same voltage of the input (the distortion on the top was already there), but the current goes higher then 5A.

I don't have a solution to this yet, but I hope you can see things I don't.

View attachment 361654

Post your asc file.
Some points of your circuit seem to be connected in parallel due to the use of labels.

 

Here. I'm planning to deal with the distortion problem of the first amplifier later, but i don't think this is a source of problem. Anyway, I'm not seeing any unwanted parallel connections here.

 

Label the nodes (Net) so we can know what the plots are showing.
V(N011) tells me nothing about where that is.

 

The input LED diode must be forward biased for proper operation, so the top circuit is the only one doing that for a positive input signal.

Also Vadc- is +5V but should be -5V

 

Are you only simulating the circuit in LT Spice or testing it in real life with a oscilloscope too?