Given the high cost + rarity of b7971 tubes, I would only recommend a current-regulated driver for each segment. Using individual cathode resistors will limit the current, but it's not well-regulated and will vary tube-to-tube and with age. Yes, the HV5530 will *work*, but I would be concerned about reduced tube life.
Also, I would not multiplex these tubes because the brightness will be reduced. Boosting the current to compensate for this will likely exceed the datasheet limits and shorten tube life. In fact, driving all segments of a b7971 tube at their rated current *at the same time* will exceed the spec limit for maximum anode current. So, along with limiting the current on each segment, you should also have a current-limit for each anode. I spent a lot of time gathering & analyzing data on my 7971 tubes to get a tradeoff between segment-current, max-current, and brightness. I know it sounds like overkill, but a few extra $ for components to protect a $100 tube is well worth it. Besides, I had a lot of fun designing and simulating the driver circuitry. The HV series drivers aren't necessary for current-regulators; you can use TTL or LVTTL shift-registers (74HC595) to control the driver transistors (PMBTA42DS). I haven't had the time to fab the PCB for my 7971 tubes yet; once I get the board running I'll post schematics. Just too doggone busy with my day job..... -- 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 neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/bc9c30db-dabd-47e0-b890-860d6b3cef13%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
