DIY Digital Lab Power Supply: Part 1 - Ec-Projects

In this series I am going to build a digital lab power supply with voltage and current control!
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[saviorsix]

So happy you are getting back to making fundamental useful equipment. Can't wait to follow along with this project! CC and CV....awesome

[akarshagarwal]

next part please. I'm very excited about seeing this circuit working in practice

[sokauo]

Thank you very much to share your videos, i'm building my own power supply and i have followed your circuit for the voltage regulation which works realy well.
For the 5v referenve i've used a 7805, works fine. Without this regulator the output voltage was droping a lot on big loads, but now it's working really well. Perhaps i will try the current regulation later.
My transformer is a toroidal 12/24V AC so i've used a 3pin switch to switch the secondary when needed so the transistor doesnt disipate all the power when working with low voltages. I can go 0 to 15V and 0 to 28.8V with the switch.
Anyway thanks a lot for sharing.

[nickpelov]

can't you connect second opamp to the middle of voltage divider and switch it's inputs (- to Vref). When ever the current gets too high it'll rise voltage divider voltage and the first opamp will reduce the output. You can also put a gain (negative feedback) on the second opamp because it works like a comparator and it might not be much stable. Use gain of 30-50 for example. Maybe also an integrating cap between - and opamp output.
P.S. Because opamps have push pull output it'll also drop the voltage of divider to 0 if the current is below the threashold. So on the second opamp you need a diode with the anode facing the output of the opamp.

[therasmc]

Fellow Dane really looking forward to this series, your explanations are great :) I need a CV/CC PSU, so I might build this alongside you

[leighrobinson]

If you are aiming to dissipate the least amount of heat and thus stay quiet, did you consider if having a switching pre-regulator that tracks the desired output voltage by a small offset might be a fun thing to try once you have the main regulation working?

[AzCcc]

For some reason I always felt you'd come back to the diy power supply(probably because you either said that or hinted it in a previous video :P). Looking forward to the next video. A little bit off topic, what would you have done to the other power supplies to reduce the noise?

[FixDaily]

Is it better to use a transistor (for the constant voltage side of the powersupply) instead of a mosfet? I'm trying with a logic mosfet and the output is not that good

[daskasspatzle]

And next comes the water cooling for the power supplies with the loud fans?

[coceth]

Any reason you chose a bjt over a mosfet for the switching?

[adilmalik]

dont use a discrete diff amp for the current control. Even a 1% or less mismatch in the resistors will ruin your CMRR by a huge margin and degrade accuracy. use a diff amp IC!

[nicktohzyu]

why not do a buck converter instead? much less heat to be dissipated

[PriorUniform]

I am really excited to see more of this project. I am planning my own PSU right now also.