adjustable multi output regulator

[reeve1987]

i everyone, firstly, thanks for taking the time to read and hopefully help me out.

im not an electrician but have some fair know how for small electrical projects, but i could use some majour help on this project i have going.

basically im looking to take 1x 12v NiMh rechargable battery and run 3 devices from it, but i would like to be able to route its power through to 3 outputs where i can manually adjust the voltage and amperage of each output.

the outputs im looking at getting are 12v, 2000Ma and 2x 5v 1amp outputs, but both factors for each output MUST be variable between 1v - 12v and 0.5A to 2.5A (or higher).

im looking at placing the circuitry onto a basic breadboard for testing initialy then over to one of those copper plated boards with the holes in, (project boards?)

so i'd really appreciate some straight forward/easy to read instructions or schematic with what components to use.

can anyone help me out with that?

thanks again for reading and hope someone can help me out.

 

[spark 68]

There are many adjustable regulator circuits on the net, these can range from relatively simple to quite complex.

Just one word of advice, if you want to avoid the more complex switch mode type regulator circuitry, then you will need to supply more than 12V to the input of the regulator, to be able to regulate down to 12V, also taking into account the voltage drop across the regulator.

 

[reeve1987]

unfortunatly the highest voltage battery i can go to is 24v i think.

im basicaly looking to make the whole thing myself, i just need something to be able to adjust the voltage and ampage on each channel manually. kinda like how pots work but for voltage and amps

 

[spark 68]

unfortunatly the highest voltage battery i can go to is 12v i think.

If thats the case, then you will be limited to the switching type regulator, as you cannot get out more than you put in (voltage wise) with the simpler linear circuits.

As I said there are many different circuits available free on line, I would suggest an Electronics forum.

There are many topolgies for this type of circuit, probably using a purpose designed IC would be the easiest solution, again these range from fairly simple to quite complex.

Adjusting the voltage is not so much the problem, but by adding adjustable current limiting at the range of currents you require, is adding another layer of complexities.

 

[reeve1987]

hi sorry i did edit to say 24v.

im not to worried about making a complicated circuit, i pretty much thought it owuld be

 

[spark 68]

A google search for 'Adjustable psu circuits' throws up many pages, similarly does 'DC-DC converter circuits'.

There are many data sheets from Maxim etal. with application circuits, which you can adapt to suit.

An electricians internet forum is not really the best place for the such a wide ranging and complex subject of psu design, as I said earlier there are many published circuits available free, which will be suitable for modification, and will enable you to tailor them to your own requirements.

 

[reeve1987]

okay i'll try else where because none of the ones i've found have the voltage and amperage adjustment features im looking for, they're all either way off the marks needed or lack one or the other.

someone else where had recomended this forum for help and i remembered i had an account.

oh and those curcuits you said are out there, they're all for single outputs, this one needs 3 outputs

 

[spark 68]

oh and those curcuits you said are out there, they're all for single outputs, this one needs 3 outputs

Yes I know, it means you will have to run three in parallel, or in series parallel or other combination, the 0-5V ones after the 0-12v ones, either way you will need to build three similar 'channels', if you require three seperately adjustable outputs.

 

[reeve1987]

i dont mind building 3 as long as they're on the same prototype board. i just need help finding the schematics in a simple easy to follow way which i cannot find.

im sure i can work out how to get them all on the same board easily enough

 

[spark 68]

im sure i can work out how to get them all on the same board easily enough

To be fair to you, there are a plethora of circuits out there, Short of designing one for you, I have given you enough information to help start you off.

I do come from an electronics background, and I would be normally commissioned to design such a PSU.

 

[reeve1987]

not really, ive searched for the schematics needed and not had luck, otherwise, i wouldnt be asking on forums.

im not going to pay someone for something thats freely available. if you wont be of any real help, i will find someone else who is.

i dont mean to sound ungrateful, but its not much to ask of anyone that when they rant on about information being available online they provide links for what they're looking for. if you came to me asking about computer related stuff, i'd be more than willing to provide links or documentation on the subject because i know its out there for free and providing that IS being helpful instead of just saying "google it"

 

[spark 68]

DC-DC Converter Tutorial - Maxim

DC-DC converter using LM2576

DC-DC Controllers, Converters, & Regulators

Have a look through some of these websites, there are many, many others.

Without meaning this in a nasty way, as I said earlier, this forum is an electricians forum, and not really the place for this subject, which is about electronics, if you require step by step instructions, have a look on an electronics forum

 

[reeve1987]

okay well for someone who isnt sure what they're looking at hence asking for help, i will await someone elses assistance, either from here or elsewhere.

thanks all the same

 

[spark 68]

Iam trying to help you, by steering you to the correct places to look for the information you require.

What Iam not prepared to do, is get into electronics circuit design on here, which is off topic for this forum.

The websites I posted above have more than enough information available to enable someone who is capable of electronics, to tailor the basic application circuits to suit their requirements, and there is a vast array of information available elsewhere on the net.

Here is an attachment of a relatively easy to use device for the adjustable voltage part, you will require three (for triple outputs) of the adjustable types, you will also need to add a foldback current limiter (adjustable) to each output, which you can search for on the net, this part of the circuit should be fairly easy to arrange.

 

[HandySparks]

spark 68,
I think you've been remarkably helpful to the OP. I suspect that he's trying to make too great a leap from his existing knowledge.

To the OP,
Loads of PSU designs, kits and modules available. How about these from Quasar for example?
Power Suppy Kits, Projects & Modules

If you gave a bit more background (why you need both adjustable voltage and adjustable current limit), you might find a better solution. But as spark 68 says, there are better forums for this.