SG3525 feedback with opto

[medogrizli]

If I use feedback with trimer resistor I can trim all range of voltage output:

IS IT possible to vary all range of output voltage if OPTO is used, and what kind of circuit is required😀

 

[shortycap]

Hi medogrizli 🙂,

What did you use to model your SG3525?
I am currently using a student PSPICE Edition and have not found
the model. I am not quite familiar with simulations and am truly lost.

~América

 

[Eva]

If you use an optocoupler, you will also need something providing a reference voltage to which the output voltage is compared. Then the difference between those two voltages is converted into a proportional current, some gain may be added (a TL431 is the usual way), and then this current is fed to the photodiode. With such a feedback scheme, adjustable output requires just a variable voltage reference.