I have built a number of mux'ed and direct drive designs. I find that, on balance, a direct drive display appears brighter to my eyes than a multiplexed one FOR THE SAME AVERAGE CURRENT.
On some mux designs, I HAVE had singing tubes - particularly larger IN18 types, when you can hear resonances and harmonics of the multiplex frequency. Higher mux frequencies are better for display stability, but where singing IS an issue, the tubes get louder with higher mux frequencies. Hardly enough to keep the cat awake, though. I am not a great fan of 555 SMPSs, but it's not the 555 that's switching the current, but the MOSFET. Choose the right one (low Rds, low gate capacitance) and you should be able to get all the current you could reasonably need. ALL of my SMPS designs use UC3843's, Cheap and bomb-proof and I have never had any stability issues with them. I copy the designs from the data sheets, with a few extra bits thrown in from time to time. In any small simple SMPS design, efficiency varies a lot, depending on that output MOSFET and the inductor. If you want to try direct drive designs with lower chip counts, look at the serial>parallel high voltage shift registers from the likes of Supertex. Can't solder those buggers into a PCB with your plumbers' blow torch, tho! Experiment, experiment, experiment! On Aug 4, 1:54 am, threeneurons <[email protected]> wrote: > > Threeneurons, > > > I will be driving six IN-14's (not IN-18's). Think the 555 > > will do it in direct drive? > > > -Ryan > > IN-14's. Like these: > > http://www.flickr.com/photos/20801462@N00/3704107559/ > > Use to be in Wittlich, Germany, from 2004 until 2009. Now its in > Covina, CA, so I can see it regularly. My brother moved, along with > the clock. IN-14s are as clear as the day they where 1st installed. > Its also powered by a 555 supply, which also has to power that 6802 > dekatron. +450V in addition to the +200V for the nixies. Its 4x1 > mux'd. The uC is an older mega8, and it uses the cpu clock to time the > AC line to see if there's 50Hz, 60Hz, or no AC (DC) coming into the > wallcube jack. Also has a DS1307 RTC, and chimes hourly. A decaying > sinewave, which sounds like a real ding, as opposed to a beep. The > schematics and HEX code can be found on my Skydrive: > > https://skydrive.live.com/?cid=f9db37b8211ce831 > > under Electronics Projects / Nixie Clock #3 -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
