How this power supply work?

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#1
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Hi
This power supply is 3w and its small in size.
I want to build something like this.
Size matter to me
What topology should I use for such small power supply?

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It's most likely a flyback converter.

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Kartman wrote:
It's most likely a flyback converter.

from phase it going to diode half rectifier first then to rest of circuit

maybe i should reverse engineer it

 

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Maybe you should. There's not many components. The secret is in the design of the transformer.

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Kartman wrote:
Maybe you should. There's not many components. The secret is in the design of the transformer.

its looks like this 

first i should test it in ltspice

 

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How does it work? Nicely.

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

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  • "Give me six hours to chop down a tree and I will spend the first four sharpening the axe."  -- Abraham Lincoln
  • "All right wise guy, where am I?"   -- Daffy Duck
  • "Well, we're safe for now. Thank goodness we're in a bowling alley."  -- Big Bob, Pleasantville
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It's most likely a flyback converter.

 

Yes, but it could also just be a simple stepdown transformer and a linear regulator, (e.g. 7805).

 

What does the 3-lead device that looks like a transistor say on it?

 

When you talk about power supplies it would be helpful to know, at a minimum:

Vin

Vout

current requirement

 

Other factors can come into play but those are the main ones.

 

JC

 

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Doc, the core is not big enough for 3W at 110VAC/60Hz. Being ferrite, even more so.

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From the size of it, it's definitely switching.

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

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navidrct wrote:

its looks like this 

 

I don't think it does. There is a huge disparity in the number of components.

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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The case in the picture clearly states 220/240 ac, I would assume 50hz.

 

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

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Looks like a flyback with weak regulation.

Power Integrations offers  nice suite for supply design. PI chips have nice protection features. IMHO easier and safer than discrete based solution. Used in a number of appliances built -ins  and instruments.