I'm trying to design and build a simple ac/dc smps that outputs 5v dc and capable of 2 amps. I currently have it mostly designed using a nmos but the problem I'm running into now is how to get a pwm signal with 18V. Is there any advantage to using a PMOS or a NMOS or vice versa? I need to build this soon to stay on track for my project so any input is helpful! I was thinking of using a microcontroller to do the feedback but I understand that I will need a gate driver for it also. I'm not the strongest at programming so I am interested in seeing if there's any ic's or circuitry that I can design that will do the feedback for the pwm input for the gate of the mosfet. I imagine I would still need a gate driver for that option too. I appreciate the help.
Yes there is an advantage to using a PMOS, the driving circuit becomes much simpler. Although not concerning an SMPS but switching a load, my answer here might explain it to you.
There are many SMPS switching controllers, for example here Also have a look at the datasheet of the TL494, it is an excellent starting point.