Wanting to know about PSU current regulation.

[David97]

Hi, I'm wanting to build a dual channel PSU for lab use. Probably wanting something that will give me  up to 30V at 6A. Wanting t do some more reading about how the current regulation works. I have a basic idea, but wouldn't have clue when It came to actually designing and building something. Could anyone point be in the right direction of where I could do some reading about this?

I know I could buy a module pretty cheap, but I would rather design and build it myself.

Thanks, David

[Gyro]

For something of that power you will be looking at a discrete, or semi-discrete implementation, ie. you're not going to get there with 3-terminal regulators.

If you're looking at a lab PSU them you might well want to go for a linear solution rather than a switcher for minimum output noise.

A couple of options are to look at the service manuals for good quality commercial PSUs, Eg. Some of the older Agilent/HP ones. The other is to start studying the datasheet for the LM723 power supply IC - this would form an excellent basis because it contains most of the internals of a PSU, opamps, current limit etc but no power elements. The datasheet and app circuits should at least give you a useful insight.

If you're looking at a dual PSU, you would be best to look at two 0-30V 3A outputs that you can parallel to get 6A or connect in series to get 60V.

[Kleinstein]

A dual power supply if usually very much like two more or less separate supplys, that can be connected in series and sometimes also in parallel. Series connection is usually easy, parallel connection needs additional load sharing parts and is thus more complicated.

With so much power, you likely want to use at least two transformer taps, to reduce the power dissipation.

I would prefere the layout with a foating regulator, like many old HP supplies have used. This needs an additional auxialry supply for the regulator itself, but is very flexible (same board could be used for 10 V 5 A or 50 V 1 A - just change a few resistors and the transformer).

Just for learning, a smaller supply (e.g. 2 A only) will not change much, but parts get cheaper, not as heavy and cooling gets much easies. For so much power one would usually consider a switched mode supply that is much harder to build and a little more noisy.