To keep the segments warm, my plan was to use just PWM. Maybe it would be easier to add just a bias resistor for each segment. On the other hand, there are 128 segments, so it wouldn't be that simple after all. To limit the current I will configure the TLC5921 to deliver 19mA on the outputs. For the 4.5V 3A power supply I've found the AP62301WU-7. It needs just a few external components and is cheap, small and easy to solder.
gregebert schrieb am Samstag, 9. Mai 2026 um 01:56:23 UTC+2: > I also recommend current-limiting so that you dont get surge-current on > cold filaments. I put preheat hardware and software in place; during > preheat, all segments get just enough current to make them warm, but not > glowing. This reduces the thermal shock when turning them on as well as off. > > I dont have enough numitrons to generate any lifetime data, and I dont run > those clocks very often...only to gawk at them every few months. Then back > to standby. > > > On Friday, May 8, 2026 at 9:02:34 AM UTC-7 newxito wrote: > >> Good point. I will add the thermal monitoring to the firmware. I will use >> the same firmware as for the nixie calculators, I just have to add a >> numitron display driver. >> The idea is to also reuse the same case, which already has ventilation >> slots at the top and bottom. >> This is my first numitron project. I'm now designing a 3A 4.5V power >> supply that will replace the HV PSU and a new driver board with 8 x >> TLC5921. >> I'll upload a thermal image once I've finished the project. >> > -- 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 view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/c436a562-2885-48e4-b97c-f9a642634e5dn%40googlegroups.com.
