Wanted Circuit Design Ideas To Construct CC CV Power Supply

[exe]

Don't worry about 30V at 3A, see what happens at 1V at 3A given a 36 VDC source and a linear design.  Commercial supplies use custom toroidal transformers for this very reason.  It is unlikely that the hobbyist is going to source such a transformer.

Well, a custom toroid costs 60-100euro, which is I'd call affordable (even less if bought from a "third-world" country). Apart from that, what I do is I just use a pre-reg, like the one from here: https://www.eevblog.com/forum/projects/very-low-noise-preregulator-for-benchtop-power-supply/ .

If one wants to go really cheap, one can make a custom tranny by themselves. Or add extra windindings to an existing toroid.

[mvs]

Dave did a teardown of the Rigol DP832 for example.  Look at the parts count!

Parts count is not a measure of how good a design is and Rigol DP832 is a good example of this.

MOSFET in output stage of DP832 can operate outside of SOA in case of short output from high voltage levels.

Regular MOSFET are not designed for linear applications. Liv has limited Vds by design in his PSL3604 to around 12-14V. Rigol just put a beefy MOSFET (CEP80N15) with a hope that it would withstand Vds of around 40V during discharge of bulk caps (tap switching should be fast on this PSU).
Large gate capacitance of this MOSFET leads also to stability issues, so they put 1000uF caps on the outputs.

[Zero999]

Dave did a teardown of the Rigol DP832 for example.  Look at the parts count!

Parts count is not a measure of how good a design is and Rigol DP832 is a good example of this.

MOSFET in output stage of DP832 can operate outside of SOA in case of short output from high voltage levels.

Regular MOSFET are not designed for linear applications. Liv has limited Vds by design in his PSL3604 to around 12-14V. Rigol just put a beefy MOSFET (CEP80N15) with a hope that it would withstand Vds of around 40V during discharge of bulk caps (tap switching should be fast on this PSU).
Large gate capacitance of this MOSFET leads also to stability issues, so they put 1000uF caps on the outputs.

A 1000µF output capacitance makes it useless in constant current mode. It also makes it easier to fry things: set the current limit to the lowest possible, say 20mA, so the circuit being tested doesn't fry if there's an error, but oh no, there's around 100A of available instantanious current available from the output capacitor.

[mariush]

If you feel up to it, you could recreate the circuit of an old HP power supply, I've attached the PDF with details and schematic.

You could simplify the circuit and have separate transformer for the control section and a separate transformer for the power stuff and drop the lcd displays completely or replace them with your own modules.

I've also attached a 18v 2A power supply schematic ... it's also simple, just ignore the top part of the pdf with the 2 multimeter chips that just show the voltage and current, the bottom part is all the power supply.  The values are in schematic... they use the standard notation as in 821 = 82 x 10^1 = 820 ohm  , vr3 and vr4 are potentiometers, k1 is 12v mechanical relay (you can simplify schematic with smaller transformer and not use 2 secondary windings) .. and so on..

And the 3rd article is from a magazine, contains schematic list, part values, circuit board drawings etc

Also, remember that if you need some funky power ratings for resistors, you can parallel resistors to spread the dissipation over multiple resistors. For example, if you need 1.2 ohm, maybe get 4 x 4.7 ohm resistors in parallel and you'll get very close to 1.2 ohm

[Simon]

Dave did a teardown of the Rigol DP832 for example.  Look at the parts count!

Parts count is not a measure of how good a design is and Rigol DP832 is a good example of this.

MOSFET in output stage of DP832 can operate outside of SOA in case of short output from high voltage levels.

Regular MOSFET are not designed for linear applications. Liv has limited Vds by design in his PSL3604 to around 12-14V. Rigol just put a beefy MOSFET (CEP80N15) with a hope that it would withstand Vds of around 40V during discharge of bulk caps (tap switching should be fast on this PSU).
Large gate capacitance of this MOSFET leads also to stability issues, so they put 1000uF caps on the outputs.

A 1000µF output capacitance makes it useless in constant current mode. It also makes it easier to fry things: set the current limit to the lowest possible, say 20mA, so the circuit being tested doesn't fry if there's an error, but oh no, there's around 100A of available instantanious current available from the output capacitor.

i blew an LED up this way trying to run it in constant current on a supply.

[Zero999]

723 obsolete!,your  taking out of your ass!!

No need to be like that. The DIP and SOIC packages are no longer manufactured. The metal can variant is still made but is horrifically expensive, so it might as well be obsolete. The LT3081 is much cheaper, than the LM723.

Dave did a teardown of the Rigol DP832 for example.  Look at the parts count!

Parts count is not a measure of how good a design is and Rigol DP832 is a good example of this.

MOSFET in output stage of DP832 can operate outside of SOA in case of short output from high voltage levels.

Regular MOSFET are not designed for linear applications. Liv has limited Vds by design in his PSL3604 to around 12-14V. Rigol just put a beefy MOSFET (CEP80N15) with a hope that it would withstand Vds of around 40V during discharge of bulk caps (tap switching should be fast on this PSU).
Large gate capacitance of this MOSFET leads also to stability issues, so they put 1000uF caps on the outputs.

A 1000µF output capacitance makes it useless in constant current mode. It also makes it easier to fry things: set the current limit to the lowest possible, say 20mA, so the circuit being tested doesn't fry if there's an error, but oh no, there's around 100A of available instantanious current available from the output capacitor.

i blew an LED up this way trying to run it in constant current on a supply.

The risk can be minimised by connecting the LED first, then applying power.

I've being toying with the idea of making a CV CV power supply, with a fast current limit. The key is to use minimal, ideally no output capacitance, but it compromises stabilty and operating in the CV region, which is where it'll spend most of its time. On the other hand, most circuits which require good transient response, will already have decoupling capacitors, so it's less important than most think.