NIXIE TUBE DRIVER MODULES Part III - HV POWER SUPPLY

Before we look at preparing the Arduino/Freeduino microcontroller for connection to the nixie tube driver modules described in Part I and Part II, you can build this power supply to provide the high firing voltage required by the nixie tubes. This switch mode power supply easily outputs 50 mA, which is more than most, and offers a variable output from 150 to 220 VDC, when driven by a 9 to 16 VDC source.

Step 1: About the Circuit

A 12 volt source at one amp will easily drive this nixie tube supply. There is sufficient power produced by this switch-mode supply to drive at least eight of the nixie tube driver modules (I've had 12 of the nixie tube driver modules running off of one of these boards, that's 24 IN-12A nixie tubes!).

A typical nixie tube power supply offers 170 to 250 VDC at 10 to 50 mA. A switch-mode power supply is desirable because it's small and very efficient. You can fit it inside your clock and it won't heat up. The schematic for the project is taken directly from the MAX1771 datasheet, however, because of the large voltage jump from input to output, board layout and low ESR type components are critical.

Comments

[Satchmoeddie]

A toaster oven? Hmmm? I remember using a very dainty weller iron, and now I have the hot air rig. I may start using SMDs a lot more. Bush took away all the WMDs. ROTFL Seriously the through hole is OK, and I like it for my guitar stomp boxes and amps for ruggedness, but SMDs are a whole lot faster. A neighbor works at a board etching facility. I usually forgo any solder mask and just have him etch stuff. Thanks for the tip(s)! I have some Boroughs Nixies and do want to make a clock or thermometer, or both. I used a tranny from an old Fisher tube tuner that ran 155V CT. How do you do the time keeping and display parts? These Buroughs were to be used at a Nuke power plant, and have the radiation symbol on them. By the time the plant was finished 7 segment LEDs had replaced the NIXIE tubes. I can probably still get them new for $4 each, maybe $5 or $6 now.

[gluplug]

Hi Satchmoeddie,

Microcontrollers make everybody happy. You can try some Arduino flavour solutions, and drop in some code.

[Satchmoeddie]

Thanks! I saw some people referencing power supply options. I got a Digitech guitar synth stomp box, midi in/out/thru, and while I was at the thrift store tried buying the missing power supply. Anymore the low volt DC stuff is rectified on the mains/line side and then puts out whatever the mfgr wants using a regulator on the secondary side so the mains can run from 90 VAC to 260 VAC, After that an automotive inverter or neon/florescent transformer can be used. I just dropped the supply voltage to I believe 4.5 VDC and got a nice supply for NIXIE tubes. It replaced the dead one in an old Freq counter/clock my 2nd cousin once used. He was the engineer in charge of keeping the Atomichron at a stable temperature back in the 50s-60s.I got a lot of neat stuff from that estate that everyone else deemed as obsolete "junk", including lots of engraved base 300B tubes, 350Bs, and other WECo stuff. Since the primary coils that ran just the display on the old freq counter were fried and it was designed to work anywhere I opted for the DC Wall wart and an step up from a low DCV. Jim used to work on the clock in France too. All his stuff was universal mains power.

[sealman]

What if, anything would have to change to allow for voltage in the range of 80 - 220 VDC. Also very well done.

[gluplug]

Hello Sealman,
Much has gone in to designing this SMPS circuit so that it operates over its range of 150-220VDC. Due to the nature of the way SMPS supplies produce their power, it would be quite a challenge for it to both boost power and operate over that broad of an output range. You might get a solid 80-150 VDC, but it would involve completely redesigning the circuit.

[sealman]

Thank You for your quick reply. I had already decided that it was going to take a lot of change. Thank you! Great work

[lego51]

Any chance we can get the eagle cad layout of this board like with the other 2? or can we still order one from you guys??? Any help would be apreciated.

[gluplug]

If you look closely, it's included in the Instructable.

[lego51]

Awesome! found it! Thanks :)

[Brock_lee]

Is the PCB available for purchase somewhere or does anyone know of a through-hole equivalent for the  Maxim 1771? Thanks.

[gluplug]

The DIP version of the Maxim 1771 is available here, or here. 

[Brock_lee]

Wow!

Helluva quick response.

Thank you so much.

[robbiedesmith]

The original author of this circuit (my dad) designed it in 2003/4.

See: http://www.desmith.net/NMdS/Electronics/NixiePSU.html
For full details.

[gluplug]

Credit to your father's circuit is in the post.  I did ask him if it was okay to offer his kit for sale, and he did confirm that this was okay.

[whoop_john]

Too true Robbie. I know your dad and he's a really cool and generous person. Ogilumen also copied your father's nixie power supply design.
I do think people should give credit where credit is due.

[albylovesscience]

sweet tell him i said thankx for the circut

[filmo]

Would this design be suitable for driving the Nixie IV-18 VFD tubes? I haven't worked with any of the Nixie Tubes yet, so forgive my ignorance. Here are the specs I got for the IV-18 VFD tubes: • Cathode voltage: 5V • Working Cathode current: 85 mA • Segment voltage: 35-50V • Working segment current: 8 mA • Grid current for single position: 11 mA • Grid pulse voltage: 35-50V • Grid pulse duty cycle: 10 • Max reverse grid bias: -7V • Nominal reverse grid bias: -5V

[gluplug]

There's a really great resource on these tubes here. Note that the maximum anode voltage is 50 volts only. The HV power supply in this Instructable operates between 150 and 220 VDC.

[filmo]

Thanks. I thought that might be the case. Thanks for the great link. It's super helpful. Looks like playing with vacuum tubes is a big step up from playing with LEDs.... :)

[fcamatti]

Hey! Where do I find that Solderplus???

[gluplug]

You can request free samples here. When delivered, it comes in an insulated package to keep it cold.

The part number for the solder paste used in this instructable is: SN96.5-511-F I've had very good results using this particular paste, though you'll find many variations on the EFD web site.

[thermoelectric]

Such a good device I would make it (if i had a Nixie tube) Awesome 5 stars

[DarkStarPDX]

Awesome, awesome, awesome. Thank you!

[Sandisk1duo]

yay high voltage!