Is it possible if we run AC analysis using general current PMW controller & not the actual PWM controller specified by the vendor? Reason is because I asked the chip maker regarding their SPICE modelling however they don't have that modelling for that specific model. My actual part is High-Voltage, Quasi-Resonant, Controller Featuring Valley Lock-Out Switching

I'm wondering on how power supply designer do their compensation during AC simulation without using the actual model. Is there any "general model" that can be use as reference during the initial small signal simulation? Or they using hand calculation?

I'm thinking to do modelling from C.Basso A Quasi−Resonant SPICE Model Eases Feedback Loop Designs using SIMPLIS for my flyback QR converter.

I'm not expect the result will be totally same but I'm hope that it can help me to do estimation of compensation on my power supply

I'm also trying to understand & derive the transfer function of this flyback QR, however it is really difficult for me (maybe lack of understanding in control theory). Does anyone have tips on how to learn & improve this?

I need your advice because I'm worry that I'm take the wrong step to do the analysis.


  • \$\begingroup\$ QR controller works with variable frequency depending on the output load, so if you implement a fixed PWM frequency so called fixed frequency fly back controller, it will actually be for only 1 point of load and not the full range. if you can modelise a frequency variable Vs output load this will be more closer to a QR controller. \$\endgroup\$ – Delphesk Feb 21 '20 at 12:53
  • \$\begingroup\$ Calculate what you can, design a prototype PCB with test points, populate it, analyze it, tweak any components needed, test, tweak, final board, certification.\ \$\endgroup\$ – rdtsc Feb 21 '20 at 13:34
  • \$\begingroup\$ Better yet. Copy the demo board design, BOM and layout. \$\endgroup\$ – Tony Stewart EE75 Feb 21 '20 at 14:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.