Thank you very much for providing valuable information. As for B7971, what I meant to say is that 17mA would be the maximum current per tube (sum of current from each cathode) in case all segments are lit up at the same time (although this will rarely happen, obviously) and thus, that the power supply should handle 6x 17mA current when modified. I am aware that each segment has a specific maximum current defined as per datasheet, I have implemented current control in each cathode, as per @gregebert's suggestion last time we discussed it. I'm talking about a different "display board" for B7971 here, I don't plan to use the same one I use for IN-18 of course.
Dana srijeda, 16. siječnja 2019. u 18:12:28 UTC+1, korisnik SWISSNIXIE - Jonathan F. napisao je: > > Why do you plan to drive all the segments of a B7971? Do you realized that > this would need a resistor on each cathode? If you use one anode resistor, > the current changes depending on how many cathodes are grounded. This > results either in tube damage or not working/darker display. I suggest to > multiplex this tube. > > About the mosfet, 21A or even 32A is overkill, but the problem is, that > usually mosfets that have a low RDSon and GateChange, have a lot of current > rated. If you use a Rsense of 25mOhm, the maximum current would be areound > 3.5A@5V, so a mosfet with a few amps more should work fine, but low current > fets usually have higher RDSon. This is why most DC/DC Converters use > overkill Mosfet. > > Rdson and GateChange influence the efficiency of the circuit, so lower is > better, your chosen mosfet has 160mOhm, you could go lower. I've used the > FDPF44N25 a few times: > https://www.mouser.ch/ProductDetail/512-FDPF44N25T > > The Inductor looks fine. > > > -- 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/msgid/neonixie-l/861f31bc-ec52-4225-b24a-2bbc24e08771%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
