Anode power supply for VFD display ( 5v to 80v stepper PSU )
For my next project (another VFD clock ;), I need a small variable PSU. The main issue with the VFD display, is the power supply. In fact you need 2 differents PSU:
- a 5v / 100mA for the filament
- a variable 20 to 75v for anodes..
VFD tube like the IV18 need something like 20/30 volts in direct drive and 50/70 volts where they are muxed. As I can not use them in a direct drive, I need a psu that support output from 20 to 75v, by this way, I can dim the display easily and test the whole stuff in a direct.
I already have done several nixie PSU, but this time I want to build something small (doesn’t cost a lot) with really common parts. I decided to look at smaller mosfet, and I found the BS107 .. small TO92 package and 200v ;)
Here the schematic:

With this simple stuff, and a little microcontroler, you can step the output easily. You can use a 220uH inductor with a 5v VCC, or a smaller one 100uH if you have a PSU between 6v to 15v.
/Enjoy the next step
- Simple negative power supply (-5V / -12V / -15V)
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- IV-18 VFD vacuum Russian Clock (part 2)
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- IV-18 VFD vacuum Russian Clock (part 1)
admin December 26th, 2006
- Electronics
- Comments(1)
The BS170 is another candidate, because the BS107 has a high Ron (~25 Ohm), and the BS170 not. But the BS170 max output is 60v..