Here's the general idea:
Just a textbook TL494 circuit, right? Well, maybe the L-snub isn't so textbook, but it does work to impose deadtime. Anyway, I haven't verified if it's something about the rest of my circuit (not shown), or if the TL494 is behaving weird. But whatever the case, this circuit draws an awful lot of current on startup for 0.2 to 1 second. Enough that my 7812's output bogs down and I can hear supply ripple buzzing the GDT. Once it clears out the cobwebs or whatever, it keeps on working correctly like it's supposed to. Sorry, I don't happen to have any waveforms on hand. (It's a transient thing anyway... okay, one of the few things DSOs are good at. ;-) )
What makes me suspicious is this: putting a 10 ohm resistor in series with the GDT's CT fixes the problem completely.
So what I don't get is, what are the outputs doing at startup? Under normal conditions, I don't see any startup blip. So how does it know that there's a resistor there? Magic?
Tim