I'm trying to design a three level PWM circuit with feedback and i'm struggling to understand the feedback aspect.
The design is based on this design by Texas instruments and modified to suit three level.
The design works if B is not added to the feedback loop.
As soon as i connect B to the 10k resistor, the circuit completely deteriorates.
I'm certain I don't understand feedback properly and am hoping someone can tell me what the issue is here or can direct me to relevant feedback literature.
The PWM is for a class D amp and i'm taking the feedback before the switching stage currently but intend to take pre filter feedback later on. Am I okay in assuming the feedback in this circuit is a good indication of what it would be like in a full amplifier circuit minus the switching error?