HV Nixie DC-DC Switching Power Supply

  • Michail Papadimitriou
  • moderate
  • Tested
  • SKU: EL35901
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Nixie tubes need about ~180Vdc to light up and thus on most devices, a DC-DC converter is needed. Here we designed a simple DC-DC switching regulator capable of powering most of Nixie tubes. The board accepts 12Vdc input and gives an output of 150-250Vdc. The board is heavily inspired by Nick de Smith’s design.


The module is based on the MAX1771 Step-Up DC-DC Controller. The controller works up to 300kHz switching frequency and that allows the usage of miniature surface mount components. In the default configuration, it accepts an input voltage from 2V to Vout and outputs 12V, but in this module, the output voltage is selected using the onboard potentiometer and it’s in the range 150-250Vdc. The maximum output current is 50mA @ 180Vdc.

The MAX1771 is driving an external N-channel MOSFET (IRF740) and with the help of the inductor and a fast diode, high voltage is produced.

MOSFET has to be low RDSon, the diode has to be fast Mttr, typically < 50nS, and capacitors have to be low ESR type to have good efficiency.

Precautions must be taken as this power supply uses high voltages. Build it only if you know what you are dealing with. Don’t touch any of the parts while in use.
Pay attention on the placement of C1 tantalum capacitor, as the bar indicates the anode (positive lead)


Parts List

R11.5M - 0805 SMDC118025
R310k 0805C269724
R45k trimmer SMDC128557
Rs0.05 Ohm - 0805 SMDC149662
C1100uF Tantalium SMDC122302
C2, C3100nF - 0805 SMDC396718
C44.7uF / 250V SMDC88702
C5100nF / 250V SMD 1210C52020
ICMAX1771 SO-8C407903
L1100uH / 2.5 AC2962892
Q1IRF740 D2PAK (TO-263-2)C39238
D2ES2F-E3, ES2GBC145321, C2844160
X1, X2Screw Terminal - P=3.5mmC474892

Oscilloscope Measurements

Yellow is the MOSFET Gate voltage and Green the output high voltage (~180Vdc). We see that the transistor switches with a low frequency of 146Hz and with a peak gate voltage of 12.8V
zoom in to the above short pulses reveals 3x pulses with 48.7Khz frequency to the gate of MOSFET. Also, the peak to peak ripple on output is 6V
further zoom to the output ripple reveals some short ringing and the peak ripple voltage.


The module’s efficiency is calculated for two output currents (50mA and 25mA) at 180Vdc voltage output and 12V input. In the first case, the Pout = 8.1W while the Pin=10.96W, so efficiency is calculated at 73.9%. In the second case, the Pout = 4.1W while the Pin=5.52W, so efficiency is calculated at 74.2%. We see that for lower currents efficiency is a little greater than for the maximum current of 50mA.

Gerber View


If you would like to receive a PCB, we can ship you one for 6$ (worldwide shipping) click here to contact us

MAX1771 Datasheet

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Hi, what is the nominal and or maximal output current @ 180V ?
And you say that i can be powered from 2, to 16.5V. Is it really 2v or 12V ?
Thank you !


Poor Layout

Dustin Williams

where is your design ZF

Julian Lützen

I think it’s better to have more clearance to GND at the HV Output at the bottom side of your PCB. It seems there is a distance of less 1mm to GND. I would let end of the GND polygon about 1cm before the HV Connector and connect the HV-GND Pin with a single strip to the polygon. It feels a bit safer this way.


Hello, I am not an expert in mosfets but I wanted to know if I can replace the IRF740ASTRLPBF with IRF740STRLPBF (same reference without the “A”). The datasheet is quite similar and I don’t know if the difference matters for this application…



I would like to use this project, but I can’t open the eagle file. It is corrupt. Can You help me?



Unfortunetly still wrong. Eagle 7.6 and EasyEDA still can’t open the .brd file.


In EasyEDA when I try to import the .brd, it says:

“Unexpected error while converting. Perhaps unsupported file type or program bug”

Can You open it in EasyEDA?


It works! Thanks!



Can this power supply do 180V 30-35mA with 12V in?


And What about heating?


Perfect. The PCB already here, i waiting the components. I hope it will be good for me.


Dear Mike! I set up the power supply.On my 6 tube nixie clock the values are this:

In the morning, when 5 tube is in work (0:00 – 9:59) the current is 15-18mA @ 180V
After that (10:00-23:59) when all the 6 tubes are in work the current is 19-22mA @ 180V. The Induction is getting hot. Is this normal, or i make something wrong?



~50°C in 30 minutes


Which type / size?


I also get a very hot inductor – any guidance on suitable bigger inductors? (I get a steady 20 ma @ 200V – but it heats up pretty fast and by 30-45 minutes gets hot enough to melt 3D printed ABS parts)


Just to say thanks very much for providing this design and the parts list.
I’ve now completed my FLW project that I purchased the tubes for back in 2016.
Two of these circuits on the PCB driving 2 B-7971 tubes each.
Almost 180V right out of the box because the 5K trimmers were supplied centred. Nice!

sebastian simone

Hi, I have a module similar to this and I’ve got a question: How would you fix this to the chassis when using the module? This and other similar implementations of HV SMPS commonly don’t have holes for separators. Any Ideas?

Thank you


Hi, I am curious if I can use a more low voltage, high amperage 3.7v Li-Po to power this. Is there change I have to make with the schematics?


How do you increase the output current for this?
(say I want it to give me 80mA)


Hi! Thank you very much for sharing your project.
I was wondering which criteria have you followed in order to choose the inductor inductance and wether it is working in continuous or discontinuous current mode. I also felt curious on how did you decide Rsense value. Maybe using datasheet’s graphics?
Thank you very much once again.


I would like to know whether the HV Nixie DC-DC switching power supply is RoHS compliant?
Thank you!


Awesome. Could be customized to have the SHDN for turning off the power supply/ HV output


how can adjust the circuit to be powered on 5V? it is more convenient since any smartphone 5V charger could be used


Normally when someone copies a design, they reference the original author prominently in the article and at least ask permission.

This article is almost a direct lift from my own work at https://nick.desmith.net/Electronics/NixiePSU.html – a design that’s been published for more than 15 years and has been used multiple times.


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