In the case of galvanically isolated AC to DC converters, a controller IC is used to regulate the output voltage of the converter.
The feedback pin is fed a signal from an optoisolator driven by the voltage on the output side of the converter.
Does this optoisolator provide a binary or analog signal to the feedback pin? I am confused as to how the feedback pin senses the output voltage using an optoisolator.
The data sheet I was looking at https://www.fairchildsemi.com/datasheets/FS/FSCQ0765RT.pdf
Thank you
