A very neat drawing, I will perhaps look at digikey when I have time.
It can be neat and convenient, but it's not particularly quick to use.
I am wanting to produce about 400V, I will start a thread, asking for help.
For low current, using a transformer instead of an inductor will allow you to get higher peak voltages. As I mentioned earlier in this thread, this design topped out at 90V, probably due to the diode or the mosfet (it can't have been good for the capacitor either).
What does R2 do or IC1b for that matter?
R2 seems to be left over from the design in post #4 when feedback was applied differently. I don't see any need for it now.
Kris has it exactly right on both counts. I think I removed it at some point, but it wouldn't have made any difference.
[/quote]IC1B is needed because when Q2 conducts and disables the oscillator, IC1A's output will go high, but you want the MOSFET to turn OFF.[/QUOTE]
Yeah, all I wanted was the mosfet off when the output voltage was too high. There are probably several ways of doing it, but this was the simplest and the inverter was already just sitting there.
I could have used another transistor and a couple of resistors to pull the oscillator's gate input high, but that's more components. This was initially designed to be as simple as possible and use the smallest number of components.
Good one Steve, I use that sort of oscillator all the time in non critical timing applications. I did something similar a few years back when I made use of the high voltage produced by the coil to charge up a capacitor for an electro magnet.
My original idea came from a suggestion to use the output pin of a microcontroller to generate a higher voltage. And yes, I like to use schmitt triggers for various non-critical timing, pulse shaping, pulse extending, missing pulse detection, etc. applications.