POWER SUPPLY ISOLATED

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black03
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Post by black03 »

Hi, I need to do a power supply with isolated outputs, and some of them support more than 100ma, someone can help me with information.
all the sources and schematic that I see are not isolated the outputs, and in some of them lie with the information of the packashing, because the connectors are isolated only.

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Post by ppluis0 »

Hi black03,

Take a look at the schematic posted at this link viewtopic.php?f=1&t=4300&p=121419&hilit ... or#p121419

Disregard the tube related part of that diagram, and see if the supply sections using LM317 can ba usefol to your project.

Cheers,
Jose

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black03
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Post by black03 »

ppluis0 wrote:Hi black03,

Take a look at the schematic posted at this link viewtopic.php?f=1&t=4300&p=121419&hilit ... or#p121419

Disregard the tube related part of that diagram, and see if the supply sections using LM317 can ba usefol to your project.

Cheers,
Jose

Thanks but I'm looking for something that supports 2amp and this does not help me, but it seems that nobody has information to contribute

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Post by soulsonic »

The most straightforward way I can think to have isolated outputs that can deliver 2A is to have several individual power transformers. It would be several separate supplies inside one box. There are some multi-tap isolated transformers available, but I don't know any with windings that can deliver that high of current.

An LM317 can do higher current with a few components added. There are example circuits of this on the web and in books.
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Post by soulsonic »

This transformer includes 1 high powered 2A 9v winding, along with eight 11v 300mA windings. If you only need one of the outputs to do 2A, then this would be a good choice. I've made a supply with this transformer before, and it worked very well.
https://www.tedweber.com/wpdlxfmr-1
They also have an international voltage version.
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Post by Ice-9 »

black03 wrote: Thanks but I'm looking for something that supports 2amp and this does not help me, but it seems that nobody has information to contribute
To clarify, are you saying you NEED each isolated output to have a 2A output current, or 2A overall ? 2Amps is quite a lot from each output, what effects are you using that require such a high current ?
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by black03 »

Ice-9 wrote:
black03 wrote: Thanks but I'm looking for something that supports 2amp and this does not help me, but it seems that nobody has information to contribute
To clarify, are you saying you NEED each isolated output to have a 2A output current, or 2A overall ? 2Amps is quite a lot from each output, what effects are you using that require such a high current ?
a general option 2amp and 4 outputs of 500ma each.
and another is to filter a power supply switching, effectively the regulator filters well, but I can not find any that tolerate the 2amp.

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Post by Intripped »

perhaps i'm missing something,
but if you want to keep the outs isolated, you need 4 regulators, one for each output.

the 780x series regulator can go up to 1 Amp, so it's ok with 500mA; probably some kind of heatsink would be necessary

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Post by Intripped »

ok, I HAVE missed something... :oops:

anyway there is the 78S series:
http://www.st.com/resource/en/datasheet/cd00000449.pdf

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Post by Intripped »

also:
LM338 - 5A
LM350 - 3A

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Post by soulsonic »

You could probably connect pairs of windings of that Weber transformer in parallel to give 4 11v windings that could hypothetically do 600mA without melting.
Have to watch for phase though, and the wires don't indicate... they don't even indicate which pairs are together for a winding; had to use a continuity tester to find which were together. :slap:
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Post by black03 »

Intripped wrote:ok, I HAVE missed something... :oops:

anyway there is the 78S series:
http://www.st.com/resource/en/datasheet/cd00000449.pdf
thanks this is the solution!

Now if you can and it does not bother you, tell me with what capacitors to accompany the filtering?

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Post by Intripped »

well, i don't know, i would study the datasheet

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Post by soulsonic »

choose a capacitor who's ripple current rating is equal or higher than 2A...
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Post by black03 »

soulsonic wrote:choose a capacitor who's ripple current rating is equal or higher than 2A...
thanks, now nobody made a similar power supply, I can not see any schematic here?

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Post by Rocket Roll »

black03 wrote: thanks, now nobody made a similar power supply, I can not see any schematic here?
Power supply with multiple isolated outputs = transformer with multiple 12V outs + a number of PCB's holding the capacitors and regulators, all in one housing.

Use this board and have it made into a number of PCB's: http://www.tonepad.com/getFile.asp?id=111

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Post by temol »

Another power supply project is here.

T.

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Post by temol »

Update to my previous message - some more info on power supply project

T.

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