+/- dc power supply

NeilParbrook · 2013-02-02 10:16 am

Hi there

I am wanting to build a new psu for 2 class d amps that I have to get rid of the bricks that I am currently using.

I have seen on eBay and other sites a number of circuits for this purpose that would allow me to mask use of some toroidal transformers I have from older projects.

My questions are as follows...

Can I plug one amp into the +dc and the other into the - dc?

How can I get only + dc out of one of these boards?

Is there a better option?

Look forward to hearing from you.

Neil

sofaspud · 2013-02-02 12:12 pm

You'll need to provide more information to get the help you seek. What are the outputs of the bricks you're using, and what are the transformers you have?

Can I plug one amp into the +dc and the other into the - dc?

Probably not a good idea.

NeilParbrook · 2013-02-02 2:58 pm

The amps are able to take between 10 and 30 volts dc.
The bricks are 12v 5amp Dc.

I have two toroidal transformers available one at 18volts and one at 24volts off the secondaries.

NeilParbrook · 2013-02-02 4:24 pm

So, please correct me if I am wrong...

I parallel up the secondary's to give me a higher current output

Run it through a rectifier to give me dc voltage.

Stick a nice fat smoothing cap across the dc and that's about it.

Is that right?

sofaspud · 2013-02-02 6:50 pm

That's basically it.
You need to keep in mind things like phase when paralleling secondaries, and peak voltage and ripple voltage when smoothing the dc.

NeilParbrook · 2013-02-02 7:09 pm

Great thanks sofaspud.

Ill keep an eye on the phases but the data sheet has that in.

I have 4 rubicon 10000uF 50v caps kicking around. Do you think they'll do for smoothing?

sofaspud · 2013-02-02 7:21 pm

Yes. But be aware that the 24V transformer will likely be over 30V after rectification and smoothing.

NeilParbrook · 2013-02-02 7:23 pm

That's great, I'll run with the 18volt transformer to be on the safe side.

Thanks for you help.

NeilParbrook · 2013-02-02 8:00 pm

Like This?

sofaspud · 2013-02-02 8:19 pm

Yes. Not sure you need 0.04F for your supply. Am sure you need a fuse on the unshown primary.

NeilParbrook · 2013-02-02 8:21 pm

Should I knock it down to two caps?

I will of course fuse the primary

sofaspud · 2013-02-02 8:32 pm

I'd would at least start with two. That should be plenty. More could be added if necessary, but then I might try CRC filtering or regulation before that.

NeilParbrook · 2013-02-02 8:40 pm

Thanks for all you help.

+/- dc power supply

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