AC DC full bridge power supply

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tronicman89

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hello guys,
im designing a variable output full bridge power supply and i found an intresting design from microchip but its DC DC, so could you please help me to have AC input 230V and DC and 30V 5A as maximum output, what should i add ?..
 

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Hi,

In simplest case:
Transformer --> bridge rectifier --> bulk capacitor.

Countless internet resources show you how to. Even in this forum you may find enough informatins.

Klaus
 

thank you, for reply i just wonder if there is a way to have AC DC without transformer to have 80v 2A then connect to DC DC converter
 

Hi,

I doubt it . The cheapest (without isolation) maybe is an autotransformer.

Klaus
 

Hi,

Separate isolation transformer not required because your DC DC converter having isolation transformer
If you see all offline AC to DC converter do not have separate isolation transformer
 

thanks to all, so how can i get 80V 2A without transformer ?? because i saw many solution without transformer but they dont deliver enough current ?
 

You can use resistor divider or better resistance capacitance divider, You can also use zener diode with series resistor

80V @2A is very difficult from 230V Ac
High power loss happened in resistor
 

thank you smijesh, yes in fact that what i realise, its very difficult to have 80v from 220v ac, in fact, my board is small to have a traditional transformer so im thinking to have planar transformer but im not sure that it exists from AC 220v to 90-80v DC they offen used for DC DC, what do you think?
 

i think planar transformer is not doable due to the primary winding number so i think im obliged to use a traditional transformer, whats the smallest solution that can i have ?
 

Hi,

An autotransformer is:
* smaller than a traditional transformer
* is cheaper than a traditional transformer
* is non isolating

May I ask why you refuse to consider an autotransformer?

Klaus
 

220V to 80V 2A transformer

hello guys, in fact im working on a project and i have some mechanical limitations and i am staked to finding the smalest solution, so could you please help me to find the smallest transformer or solution to have these values 220V to 80V 2 A, thank you
 

Hi,

Don´t start new threads with the same topic.

****
Please show us where you have this information from:
autotransformer its isolated solution !
Click to expand...
hey are not a pcb mount also they have a big height
Click to expand...
It´s simply nonsense.

Klaus
 

thank you klaus for your help, in fact it have a mechanical limitations (casing) so thats why i cannot use auto transformers they are more bigger than my case
 

A full bridge, like the one you are showing, is fully capable of processing the raw (about 320V) DC directly from the rectified 230 VAC. You don't require stepping it down to 80VDC.
Of course, you will require to calculate and select the correct Mosfets, passive components and most importantly, the transformer with the proper primary ratings.

If you don't want or can't perform the necessary calculations, and simply want to copy/paste the design you have shown, then you have to use an autotransformer. There is no way around this fact.
 

Hi,

Please learn to give useful informatins.
in fact it have a mechanical limitations
Click to expand...
--> we can not know what this means: is it 1cm x 1cm x 1cm or is it 1m x 1m x 1m...

so thats why i cannot use auto transformers they are more bigger than my case
Click to expand...
That´s not the problem of an autotransformer.
In your case the 160VA autotransformer is as small as an 100W standard transformer.
They have all form options than a standard transformer: toroidal, or standard, it may be PCB mount or not, potted or not... and so on.

If an autotransformer is too big, then every low frequency transformer will be too big.

Review the thread to see how many other options you have to generate 80V/2A AC from 230V AC. I see none.

I doubt that repeatedly asking the same question will bring new results. (More than 440 times this thread has been viewed)
I doubt that repeatedly refusing facts or posting unverified statements will bring you a step ahead.

Honestly, I gave the best (smallest) possible solution that I know.

Klaus
 

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