source errors in simulation

[dbur]

Why does this simulation produce wrong data?

I know there are many sources of unexpected results in a transient simulation, but here the sources don't even produce correct waveforms.  Look at Vpwm and Vac.  Those are just source outputs and go only to the input of a virtual comparator.  How can this be?

They are roughly correct between 600-800 usec, but just bizarre everywhere else.

If I remove the mosfet from the circuit the source waveforms then look a lot closer to what they should be.

Thanks.

[dbur]

I placed an analog ground and connected it to the digital ground and that seems to have helped a lot of issues.

[Tayyab_R]

Hi,

This circuit should use only analog grounds because there do not seem to be any components which require a digital ground like gates etc.

Hope this helps.