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I want to get the bode plot of the controller part of my Buck converter. For this I looked online and saw a technique that mentioned to add an AC injection source from the voltage output to the top resistor of the voltage divider (i.e, R4). But I must have missed something as using the magnitude marker across this V5 voltage source does not work (simulation is not running). How can I get this?

I also need to change the M1 model to averaged switch model, but I need some help on how to do this after I open Edit -> Pspice Model or I think it is better to make a new model with the average switch model. enter image description here

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    \$\begingroup\$ You certainly need to resort to an average model in PSpice but you could also check SIMPLIS which will give you the ac response you want from a switching circuit, especially with resonant features as in yours. For a buck operated in voltage-mode control, check one my free 60+ templates working on the demo version and described here. If you still want PSpice, then you can implement my auto-toggling CCM-DCM PWM switch model described in the many articles I wrote on the subject. \$\endgroup\$ Feb 24, 2021 at 14:54
  • \$\begingroup\$ @VerbalKint Thanks for replying, but I haven't used SIMPLIS, I'm using Pspice right now. I can't figure out if I have to write the "new model" description (i.e .subckt statements till .ends) in a text file or somewhere else, could you clarify this please? \$\endgroup\$
    – SM32
    Feb 24, 2021 at 15:23
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    \$\begingroup\$ The PWM switch model has been described in my APEC 2013 seminar and the DCM/CCM subcircuit for OrCAD has first been presented in my book on SMPS. I recommend that you give SIMPLIS a try, the templates I posted are ready-made and you just need to press F9 to see the cycle-by-cycle waveforms and the ac response in one shot. \$\endgroup\$ Feb 24, 2021 at 15:35
  • \$\begingroup\$ I agree with Chris (@VerbalKint). SIMPLIS is well worth learning if you are going to be doing power electronics work. Also Chris has a huge amount of material he's put together that is more than worth checking out, including his book. \$\endgroup\$
    – John D
    Feb 24, 2021 at 16:31
  • \$\begingroup\$ @VerbalKint Apparently there's a new kid on the block. I just downloaded it and it looks very promising. I can't help wonder what will be the price tag after people get used enough with it. \$\endgroup\$ Feb 24, 2021 at 17:56

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