Switching regulator, for a home build charger

[FlemmingM]

Hi all

I want to build at variable voltage and current power supply, for a home build charger.

My requirement is :
Input : 12 volts
Output : 1.5 to 20 volts Variable and up to 10 amps variable.
Ex.:
1.5 volt, 5 Amp
20 volt, 10 Amp

So it has to be a switching regulator, Step Up and Step Down.
I have been looking at a lot of websites. I found many designs, but not anything that takes 12 volts as input and 1.5 to 20 volts/10 amps as output.
I know switching regulators are complex circuits to design, but hopefully someone can help whit a design.

Thanks in advance :)

FlemmingM

[Comatose]

Thats asking quite a lot. 20V out at 10 amps is going to require about 20 amps input.

If you've never designed a switching supply of any flavour before, then this would be quite a project. Not impossible, but quite a project.

The AnyVolt advertised above is step up/step down and in your voltage range, but only to two amps. Nice unit but not cheap.

The regulation in chargers doesn't need to be as good as in a standard DC/DC supply, but you're still looking at quite a project. You'd probably want buck/boost topology. Cuk or SEPIC are almost certainly going to be an excercise in frustration.

Perhaps buying a bench supply that runs from 120AC?

[Acetronics]

:) Hi, Femming

For the well known L 4970 , there's a lot of intersting designs ...from the manufacturer ( ST ) see fig. 35 i.e.
More available on the Web ...

Alain

[FlemmingM]

Hi Comatose and Acetronics
Thanks for the reply :)
Yes Comatose, I know it is difficult :confused:
We, MartinL and I, didn´t now the L4970, we have been lookingt at it and it is interessent.
But, it seems we have found what we have been looking for.
A this www-side :
http://www.sprut.de/electronic/switch/up.htm
there is a switching regulator with :
Input : 12V
Output : 2V - 30V/6.5 A (ca. 200W)
If it is working, it is perfect for the "BIG Charger" project :D .

FlemmingM

[Chippie]

Is there a specific reason for the 12v input?

far from stating the obvious....its better to start with a higher input voltage...

[Acetronics]

Is there a specific reason for the 12v input?

far from stating the obvious....its better to start with a higher input voltage...

Hi, Chippie

And how do you do, when you're on the field ??? just a car batt. available ( I'm ok a truck batt. ( 24v ) would be better ...)

Alain

[labmaster]

if you are already searching on german websites, here is another one with a very good explanation and schematics.

http://www.people.freenet.de/thhe01/modellbau/lader/lader.htm#Einleitung

regards,
Walter