Well, looks like you got it basically working, so congrats on that.
A couple of things: you are pushing the gate voltage on your mosfets to damn near breaking point - they are only rated for 20V. You only need -10V on
the gate to get those things fully turned on - anything more is just extra gate charge that will add to the heating.
Also your reference voltage appears to be just the Vbe of a transistor, which is wildly unstable with temperature - so you can expect your output
voltage to vary wildly too, as things heat up. Same goes for your current regulation.
The inductors are unshielded so likely radiating a lot of noise. Bear that in mind if you are using other instrumentation near this PSU.
Realistically, while I applaud the use of BJTs and 555's, the better route would be to use TI's Webench tool - give it your input and output
requirements and it spits out a list of suitable chips, complete with schematics and simulations. The PSU chips they have will give you an accurate
voltage reference, cycle by cycle current limiting (protect your MOSFETs), appropriate loop compensation, very low ripple, under voltage protection,
overload protection, soft-start, better EMI, smaller parts, and better that 90% efficiency.
EE's like me don't do this stuff from scratch without a really compelling reason. TI's chips are just too nice.
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