I have built a 12/24V 47A DC Power supply following this guide. It works well for running my battery chargers, but I'd like to make it a CCCV supply from it for my projects.

What would it take to do this? I've been looking around, but everything I find is either for a high voltage supply or is only a few amps.

  • \$\begingroup\$ Are you saying you want to be able to control the current coming from the power supply you have built? At the moment it is a CV supply therefore are you also saying you want to be able to vary the voltage output from the fixed-voltage modules? \$\endgroup\$ – Andy aka Oct 23 '13 at 7:28
  • \$\begingroup\$ You could PWM the output with a suitable MOSFET to lower the effective voltage, with current feedback from a low resistance senseresistor. This allow the supplies to be left unmodified. OR if you are able and willing to access the supplis internals it would probably be possible to reduce the Vout somewhat and use a current sense resistor as above to adjust current to what is desired. ... While the above may sound too hard technically, if you have a friend who is technically inclined it should be doable - with some help from this group as required. \$\endgroup\$ – Russell McMahon Oct 23 '13 at 9:31
  • \$\begingroup\$ Andy,Basically the power supply I 'built' is just a pair of repurposed server power supplies, so they output a clean 12V each and I have them in series so I have up to 24V. The current control is not necessary so if it is simpler I just want to build a circuit that comes after the power supply output to step the voltage down, but I don't want to be limited by low current. Essentially the circuit that I want to build that will come after it needs to be able to take full potential of the current available to it. \$\endgroup\$ – Austin Richard Bartz Dec 7 '13 at 2:28
  • \$\begingroup\$ Russell, I really like that idea! I'll probably run with it if the idea submitted by Ali, doesn't pan out for me. \$\endgroup\$ – Austin Richard Bartz Dec 7 '13 at 2:37

For this much current you should use a switching topology, such as a buck converter. some PWM controller IC such as uc3842, and a method to control the IC's feedback path. Some OPAMP signal conditioning for current and voltage sensing and probably a microcontroller for more flexibility in control algorithms. Most of the control circuitry and conditioning is the same as a linear regulator which you mentioned, the difference is in the PWM Controller and the output switch and output filtering. you can find a good article to improve your knowledge on linear power supply design here: Fully Programmable Modular Bench Power Supply

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