@FxDev can you share your design for HV power supply driven from the MCU ?
Of course!
I use TC4427 mosfet driver because my MCU is working with 3.3V. Of course we can use other methods but this is the easiest way for me.
On the other hand, input caps are 1206 package 100nF and 1uF ceramic. Output cap is 2.2uF/250V. L1 is 330uH, I also tried 100uH to 680uH with no problem. I use PID algorithm for control this converter. Duty is around %70-80 when nixies are working. R24 is 150k/1206 and R25 is 2k2/0805. D1 is SK120 200V schotket diode.
I finished programming, now I'm writing small PC program to configure my nixie clocks. Few days later I will publish all!
I'm just using some of Taylor Edge's smart nixies (need to get some more), and made a backplane using some perfboard. (the analog discovery is monitoring the i2c feed in this shot)
There is an easier way for the gate driver (this is also a little overkill), and that's just a simple npn/pnp totem pole.
You can do that with two transistors, or with something like a ZXGD3002E6.
Widely used in Class-D power amplifiers.
If you don't need much power I think a combination with a step-up transformer would work a little better.
I managed to get my Christmas Nixie clock project mostly completed now. I use a 62v zenner and HV5812s and have no glow on any element apart from the lit one. Just need to laser cut an acrylic case now.
My switching frequency is 16kHz.
There is an easier way for the gate driver (this is also a little overkill), and that's just a simple npn/pnp totem pole.
You can do that with two transistors, or with something like a ZXGD3002E6.
Widely used in Class-D power amplifiers.
If you don't need much power I think a combination with a step-up transformer would work a little better.
using a ZXGD3002E6 isn't the same thing as using a TC4427 ? there are basically doing the same thing.
Isn't the intention of the bias to bring the non-lit elements to a potential where they will not glow (60v giving 170-60=110v, not enough for a glow), if left to flap in the breeze then they adopt a potential which reflects their nearest element?
Here's an interesting graph... http://www.decodesystems.com/re-how-figure-5.jpg
And the full treatment of how much glow is objectionable etc! http://www.decodesystems.com/re-how-nixies-work.html
This is the datasheet of the MOSFET. I think I don't need the bias for protecting it, because Vds is 240V (and it still works after some time testing it), but I can't find the leakage current in the datasheet when it is off.
So the first question is. I know the two anodes are for odd and even digits. But do I really have to cut the anode-power of the odd digits when using the even digits, and vice versa? It really complicates the circuit more than I really want. :/
Next question: I have read somewhere that the shield input should have a ~50v input. Do I need to create a custom constant-voltage circuit to keep this pin at 50v? Or is it something you only would do to prolong the life of the tube a bit? If so, anyone have any tips on how to do it the "KISS" way?
So the first question is. I know the two anodes are for odd and even digits. But do I really have to cut the anode-power of the odd digits when using the even digits, and vice versa? It really complicates the circuit more than I really want. :/http://www.tube-tester.com/sites/nixie/data/in-4/in-4-sh2.htm suggests use just pin 4 when not in biquinary mode??
Next question: I have read somewhere that the shield input should have a ~50v input. Do I need to create a custom constant-voltage circuit to keep this pin at 50v? Or is it something you only would do to prolong the life of the tube a bit? If so, anyone have any tips on how to do it the "KISS" way?That's a topic of some debate! If you follow an existing K155ID1 design then you should be OK.
So I checked the 22k dropper resistor, and it's gone out to 51k. That explains the dimness, and possibly the partial lighting of the 9 also.
It's just an 0805 SMD part, so when multiple digits were drawing current through it, maybe it was overloaded and that is what exploded (though it doesn't look damaged).
I'm just using some of Taylor Edge's smart nixies (need to get some more), and made a backplane using some perfboard. (the analog discovery is monitoring the i2c feed in this shot)
you are also using his power supply module ? looks cool anyway, keep us posted
That's really bad, have you done the math? 0805 has like 0.1 W power rating.
Is this project dead?
That's really bad, have you done the math? 0805 has like 0.1 W power rating.No, obviously I haven't! (I don't do much SMD, and I have been caught out on that one before)
In my defense, it seems like Dave used 0805's (but possibly 1206) in EEVblog #974, and I didn't bother checking.
Anyway, replaced the resistor, and the nixie has come good now.
If it still proves to be a problem (and it seems that it will), I'll bodge on some larger resistors.
But I want to check some voltages/currents/powers first.
I would still like to know if anyone has actually driven IN12 nixies with TPIC6B595's, and how well it works.
...using 0805 footprint but solved it by using double decker... one R on top of another and doubling the value...
There seem to be some people on the interweb who have done it. https://groups.google.com/forum/#!topic/neonixie-l/NTRfqU8ASvc
Personally I went for HV5812 (might use HV5622 if I do it again)