schematic for 10A step down adjustable Buck Convertor.

[xReM1x]

Hi, I have a psu that can supply 10A and 24V.
I've used a buck convertor I bought from eBay, and it worked great I could adjust the output voltage, and I could short it no problem, until I shorted once and the dc-dc chip just blow off to 2 pieces. I tried googling the part number, its crappy generic cheeinse dc-dc convretor that I could only order on eBay, and there is no way I'm buying this crap again, + I dont want to wait 30days for it to arrive.
So I tought maybe I could build my own, and see how it goes.
as basically Input voltage of at least 24V, that I can adjust from at least 1V to 20V 10A, very stable that could handle short outs :grin:.

 

[KlausST]

Hi,

Look at www.linear.com

There is an interactive switch mode configurator. It tells you wich device to use. In the device datasheet you will find all information to build your circuit.

Klaus

 

[BradtheRad]

It is possible to construct your own buck converter from inexpensive parts.

However results are unpredictable if you short circuit the output.



Dial in a reference voltage using the potentiometer at left. The converter will maintain that voltage at the load. The load can be any value.

You may not get your spec of 20V and 10A with this simple homebrew circuit. Therefore consider interleaving two or more buck converters.

 

[xReM1x]

If ill build what linear have here : https://www.linear.com/product/LTC3778
and change once of the feedback resistor to a pot will it work?
And could I short it out no problems for at least 10 seconds every 10 seconds without fan? heatsink is not the problem.

 

[andre_luis]

change once of the feedback resistor to a pot will it work?

I can´t see any problem, considering that the sampled voltage is already damped by output capacitor.

 

[xReM1x]

I can´t see any problem, considering that the sampled voltage is already damped by output capacitor.

And what if I will short the output?

 

[andre_luis]

According to features described on manufacturer link posted above, it is stated that this controller already performs a short-circuit timer protection.