Hello Zitt, first of all, this sounds like an interesting and worthwhile application for nixie tubes! You are to be congratulated on that. I am not saying your design wont work, but you've asked for comments, so here are mine...
I do feel that you may have over complicated the LED drivers a little bit. Seems like an awful lot of semiconductors in there!. First of all, consider wiring pairs of LEDs in series, or even quads in series, depending on what (12V?) power supplies you have to hand. Then current limit them through a series resistor, and wire multiple strings of this arrangement in parallel and then back to just the one switching transistor. The resistors R56/R57 in your anode drivers are probably a bit low - you've got the best part of 2mA of (expensive) HT flowing down there. The driver transistor q21 etc. won't need that much base drive. I've used values three times yours before, without any issue or ghosting, etc. You are multiplexing this display on a "one of six" basis. That means each nixie tube is only going to see juice for maybe 15% of the time. Even if you overdrive them, they will be on the dimmer end of their possible light output, and I would imagine that for your application nice, bright displays are somethiung of a prerequisite. You might want to consider designing the mux to be two sets of "one of three". As I say, it will work as you've got it, but you may be disappointed in the results. Check the pin-outs of the nixie tubes - i think you can save maybe one or two pins (you still need the PCB holes, of course, but now electrical connection to some pins). I think 190V HT may be a bit too "hot". You may find the displays will work fine at 180V, even 170V. The tube's actual striking voltage is probably around 150V. You will need to set the anode current limiting resistors to suit, of course. That's the thing about electronics, isn't it? there are often many ways of doing it! Keep us up to date with your progress -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/FpmphJB6vA0J. For more options, visit https://groups.google.com/groups/opt_out.
