Tool/software:
Hello
I'm trying to build a simple small signal model of a self oscillating class D amplifier. Obviously the most challenging part is modeling the switching part from the comparator to the power stage. I found a few papers using a describing function theory to " linearize" this part. In one of the papers they define the gain of the switching part as half the ratio between the output square wave's 1st harmonic amplitude and the comparator's input voltage. This approach results in a very high gain (above 100) which clearly impacts dramatically the open loop response. I'm wondering if this makes sense, as transient simulation of the closed system seems to behave completely different from what is predicted by the small signal model.
Thanks