Tim and Rigby thank you for your kind answers
First off, to clear any doubts (if there were any lol) I'm a programmer who recently picked up electronics so... yes... I'm a noob
@Rigby: country updated, thx for bringing that up
A) the intended use is a buck led driver so perhaps I don't need that high a frequency?
B) It's as much for learning as is for fun as one can buy one of those for a cpl bucks on Ebay
C) yes I did
inefficient little buggers though
@Tim: overwhelming lol
afaik pin 7 is an open collector (kindly correct me here if I'm wrong).
as for the 7805: good point there!
Vdrop is typically ~2.5V@200mA, right? I can use another, higher voltage, LR, say a 7810, as I have an assortment of those in different values.
as for the LM311 not quite sure what you mean... I intended to feedback its output to the non inverting input via a 10K resistor as to give it some hysteresis... is that it?
First time I heard about TL431 .. will have to look at its datasheet again to let it "sink in" 1st lol. But thx for the reference!
For the record... this is what got me started:
http://www.instructables.com/id/Poormans-Buck/?ALLSTEPSFirst I decided that I didn't need all that mess... and got away with simply slamming a 10ohm resistor at the gate of a NFET and connecting that to one of the arduinos pwm outputs... pure 0-100% duty cycle.. nice
Then I thought I should learn more about buck converters and looking at the link's circuit it struck me how wildly frequencies would vary depending on load. So I ditched it and came up with this half cooked idea
I got to the point where I assembled the circuit and then looking at the ne555... I thought ... WTH am I doing? How in the heck am I going to connect this to both FETS *without* turning them on at the same time!
Thanks for your thoughts guys, appreciated