12V to 48V power supply of up to 16A

Thread Starter

crazybuoy

Joined Sep 19, 2010
77
I have 12V , 16A from ATX power supply by collecting all yellow cables and same number of black cables on the other side.

I want to convert it to 20, 25, 30.....48V and the input current (16A) should not be decreased, it means, there should be 12-16A with output voltage.

I have searched schematics a lot but could not decide which one to use.

Please suggest me any circuit as small as possible.
 

wayneh

Joined Sep 9, 2010
17,496
No such thing exists. You cannot create power. At best you can convert voltages and currents with minimal losses of power.
 

dendad

Joined Feb 20, 2016
4,452
wayneh is correct. You cannot create extra power.
In simple terms, If you have a 12V 16A supply, it is able to supply 12V x 16A = 192 Watts.
You are wanting to convert the 12V to 48V. There are switch mode boost circuits that will do it but that will only give you 4A. (192/48=4).
Likewise..
192/20=9.6W
192/25=7.7A
192/30=6.4A
As you see, while the voltage goes up, the current goes down.
A 48V 16A supply needs to be rated at about 770Watts.
 

dendad

Joined Feb 20, 2016
4,452
No. That circuit cannot.
That is a very simple circuit that can only drop the voltage and it is unregulated. Also it would waste a a lot of power as heat.
What you are trying to do is not as simple. Look at ..
https://en.wikipedia.org/wiki/Boost_converter

You will need an inductor that is switched to create the voltage boost and a control circuit plus quite a bit of other stuff.
All this is possible to make but if you are new to electronics it is quite a challenge. Think lots of smoke!

Here are some app note to start the calculations...
www.ti.com/lit/an/slva372c/slva372c.pdf
www.ti.com/lit/an/snva731/snva731.pdf

And some further reading...
http://www.ti.com/analog/docs/analo...&rootFamilyId=64&familyId=752&docCategoryId=1

www.linear.com/docs/26920

This is just from a Google search and I've not looked into them all as yet.

This is a good project for you to try but don't hook anything of value on as a load until you have it well working and stable. There are a lot of traps to building your own switch mode power supplies, and more so as the power goes up.

Have a search on Texas Instruments site, Linear technology, Maxim and ST amongst others.
 

tcmtech

Joined Nov 4, 2013
2,867
You will be time and money ahead to just buy a regular 48 volt SMPS unit and modify its feedback loop so it can be adjusted to putout lower voltages.
 

Dodgydave

Joined Jun 22, 2012
11,285
No, that circuit is a Flyback oscillator with a pulsed output.

You're better getting a 50V switch mode psu, and buck converter chip like Lm2596.
 
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