PC External PSU

Hi,

I need a power supply to run some PC boards outside of the Computer case, the External daughter board i'm intending to use requires 12v, 5v and 3.3v, I have three buck step down adjustable regulators. (4-38V to 1.25-36V 5A 60W Buck DC-DC Step Down Module Regulator Voltage Converter).

I don't want to use a PC power supply because of it bulk and extra wires. looking to create something neater.

The buck Regulator boards have in +/- and Out +/- Can I connect 3 in+ together to the power supply Positives and 3 In- together to Negative and bridge the 3 out- negatives leaving the 3 out+ to output the necessary voltages I require retuning to the combined bridged out- (Negatives) max 60watts each.

it looks logical but before I start,

the question I wish to ask, will this work or will it feed back and fry every thing?

Thanks for your time.

by Digit01
May 02, 2019

Voltage Converter is transfering DC voltage to DC voltage. Where your input DC voltage? Only solution may be to connect 12VDC of PC power supply out to get 12VDC, then use one converter for 5V and another one for 3.3V. Of course, the 12V DC from PC power supply should have more current than your 12/5/3.3V load together.

by wangwg88
May 02, 2019

Thanks for the reply,

I was intending to use a 18.5v laptop power brick, Via Power barrel plug.

I know a PC ATX power supply would work, but it's a large metal box with lots of unrequired cables.

My worry is that if I combine the grounds on the 3 different regulators, would I get ground looping or feed back between the regulators. causing power spikes.

Output would be by a 5 wire Sata Power Connector which was 3 supplies and 2 grounds.

Thanks for your time, Appreciated.

by Digit01
May 03, 2019

ATX Power supply is not as simple like use dc-dc converters.....they have a lot of specifications and Power good signal....I recommend to read https://www.intel.com.br/content/dam/www/public/us/en/documents/guides/power-supply-design-guide.pdf

by ale.trevizoli
May 03, 2019

I suggest buy it: https://www.aliexpress.com/item/24pin-DC-ATX-PSU-12V-DC-Input-250W-Output-Switch-Pico-DC-DC-ATX-PSU-MINI/32826517978.html

by ale.trevizoli
May 03, 2019

no problem to let 3 regulators work in parallel except you connect their positive pins into a loop.

by wangwg88
May 03, 2019
Add comment...

Please sign in or create an account to comment.


No Answers

No answers yet. Contribute your answer below!


Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account


Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers


Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.


About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.