I think I am getting a little closer to understanding this all a little bit more. I have almost grasped the concept of clamping the cathodes at an intermediate voltage to aid switching them on and off in a timely manner in an effort to minimise ghosting.
Now it's all down to driver choice and chip count. How about HV5812's? i have seen these used in multiplexing circuits - especially those where a group of say 6 nixies are split into two groups then the 20 bits from the driver are split into two groups of 10 bits, each group for one set of three nixies. that works just fine for nixies, not so good for a 16 digit device with cathodes common to all! Regardless, it would be slightly more efficient than using a 32 bit device though ultimately an 8 bit device would suffice. Using the HV5812 I can see that I can just connect Vpp to 80V, job done. If I wanted to use HV513 (on the grounds that I only need 8 bits) would I then just clamp each cathode to 80V via a suitable resistor? I guess I could simply not worry about it and waste the bits, I'm only ever going to do this once or twice and one of my design goals is to make this thing as small as possible. For the high side i definitely need to switch 16 anodes so I need to employ a push/pull device - HV5523 will do that or I could perhaps use a couple of HV513's - again, the easiest thing to do would be to use a single HV5523 and waste half of the bits. In an effort to home in on a solution - a single HV5523 for the 16 anodes and a single HV5812 for the cathodes (clamped to 80V) - have I missed anything crucial here? I just feel that I should get a handle on this multiplexing thing. I now have a couple of different multi digit panaplex displays coming so I need to come up with a plan. I have some ZM1500 (12 digits) on hand and some IGP-17 (16 digits) on their way. ... and I've not even started to think about the timing of all the various switching operations yet! Thank you all for helping me with my education - Richard On Friday, 21 May 2021 at 19:13:35 UTC+1 nixiebunny wrote: > Richard, > A single push-pull HV driver chip will not be able to drive a multiplexed > display. > > The reason is that it only connects each tube element to either 0V or > 180V. It is not capable of leaving an element disconnected. > > > On Thu, May 20, 2021, 8:45 PM Richard Scales <[email protected]> > wrote: > >> Sorry, I mean using the same type of device to control the anodes AND the >> cathodes but but the actual same piece. >> So, using an HV5523 (or perhaps multiple HV513, multiple because there >> are probably 8 cathodes (seven segment panaplex displays) and 16 Anodes (16 >> digits)) could be a way forward then. >> Please could you let me know more about the need to clamp the cathodes to >> a certain voltage? (Exposing my real lack of understanding here!) >> - Richard >> >> >> -- 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 on the web, visit https://groups.google.com/d/msgid/neonixie-l/f6ce3fc3-86db-41fe-8b2f-ff323dd729aan%40googlegroups.com.
