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Frex 29th November 2011 06:24 PM

Triple outputs 100W Laboratory PSU -- A new DIY project .
Hello all,

After being delayed several times, i start a new thread about my new DIY project : a laboratory power supply.
I had already mentioned this project several months ago but without details.

Now, the prototype PCB of this project has been made and the parts soldered.I must now test it and doing programming.

As many DIYers, i need to use power supply unit very often, for testing new electronics board, to repair hardware and for many others things...
So, i have compiled all my own needs for a PSU lab to design this new one.

It's main features are :
  • AC input 90-250Vac 50/60Hz (no PFC).
  • Resonant mode flyback design with low EMI signature.
  • Low output noise design.
  • High efficiency, low heat dissipation.
  • Compact and light design, fitted in aluminium Hammond enclosure (1455T2201 - 220x165x52mm).
  • 3 DC outputs with voltage and current limit adjustable.
  • OUTPUT A : 2V....10V 0...3A max
  • OUTPUT B : 4V....18V 0...3A max
  • OUTPUT C : 4V....18V 0...3A max
  • 100W max total output power.
  • Each output is isolated and can be serialized (not same ground).
  • 7 segments green led display for each output with digital encoder.
  • Voltage and current adjustment.
  • Current limit indicator.
  • Enable all outputs switch.
  • Tracking switch for OUTB/C for symmetric voltage adjustment.
  • Minimal internal wiring.
  • 4mm bananas outputs connector.
  • CPLD based design for V/I control.
Because some pictures are more clear than a long article, below a picture of what should look like the front and rear panel, and one of the bare PCB (not wired).

I will post soon some others documents (of course schematics and more).


thaumaturge 29th November 2011 06:42 PM

"I will post soon some others documents (of course schematics and more)."

Please do. One can never have too many supplies.

piero7 29th November 2011 07:02 PM

Very interesting ;)

cliffyk 29th November 2011 09:00 PM

Looks like a nice project, here's one I built in 1976--still on the bench and working fine...

Frex 30th November 2011 04:13 PM

3 Attachment(s)
Hello all,

Nice work Cliffyk !
I hope to built a slightly small PSU for my lab :D .

Today i was working to design a test program for the PLD.
This program will allow to easily check all functions of the PSU controlled by the PLD,
like ADC, mux , digital potentiometers, 7 segments leds displays, rotary encoders and more.

I think to start these tests at the end of this week (i'm also very busy by my job).

As promised, i post the full schematics of the PSU.
It's a un-debugged version, only a prototype board.

I will post all results as one goes along.
As you could see on the picture of the PCB, the power transformer is not yet soldered, i will build it and test the resonant flyback in a second step.
All design calculation will be also explain with expected and real waveforms.
To follow...


cliffyk 30th November 2011 07:50 PM

All analog way back then--the 2N3055s in the outputs were close to "state-of-the-art"...

Frex 3rd December 2011 01:38 PM

Test in progress...

I have written a first software for test.
It allow to test many functions separatly and easily.
The PLD was succesfully programed with, and no big issue was encountered.
  • 7 segments display multiplexing is ok
  • Digital encoder's and leds are ok
  • U/I mux and A/D converter is ok.
  • All digital potentiometers (for setting V/I) are correctly drived,
  • All bucks work fine with approximatively expected voltage range.
  • Symetric control of outA/outB is ok.
  • Output enable switch is ok.
I will try to post a small video of the test program in progress this week-end.

I must work hard now next week on the final PLD program that will include many more logics functions...


Frex 4th December 2011 03:38 PM

A small video of encoders and 7 segments test...


cliffyk 6th December 2011 12:43 AM

Very nice, sure is tiny as compared to mine!

carpin 6th December 2011 01:10 AM

Hi Frex, nice project, I want to build this psu to.


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