How this power supply work?

Log in or register to post comments
Go To Last Post
13 posts / 0 new
Author
Message
navidrct
navidrct's picture
Level: Wannabe
Joined: Sat. Mar 2, 2013
Posts: 90 View posts
#1
Posted by navidrct: Thu. May 19, 2016 - 09:44 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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?

Tags:

Learning and Information, General Electronics
Top
Kartman
Kartman's picture
Level: 10k+ Postman
Joined: Thu. Dec 30, 2004
Posts: 24773 View posts
Location: Melbourne,Australia
Posted by Kartman: Thu. May 19, 2016 - 10:07 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

It's most likely a flyback converter.

Top
navidrct
navidrct's picture
Level: Wannabe
Joined: Sat. Mar 2, 2013
Posts: 90 View posts
Posted by navidrct: Thu. May 19, 2016 - 10:18 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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

 

Top
Kartman
Kartman's picture
Level: 10k+ Postman
Joined: Thu. Dec 30, 2004
Posts: 24773 View posts
Location: Melbourne,Australia
Posted by Kartman: Thu. May 19, 2016 - 11:36 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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

Top
navidrct
navidrct's picture
Level: Wannabe
Joined: Sat. Mar 2, 2013
Posts: 90 View posts
Posted by navidrct: Thu. May 19, 2016 - 12:08 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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

 

Top
Torby
Torby's picture
Level: 10k+ Postman
Joined: Tue. Nov 11, 2003
Posts: 10367 View posts
Location: Bartlesville Oklahoma USA
Posted by Torby: Thu. May 19, 2016 - 01:34 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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. 

Top
ciroque
ciroque's picture
Level: Hangaround
Joined: Wed. Jun 21, 2006
Posts: 407 View posts
Location: Bainbridge Island, WA
Posted by ciroque: Thu. May 19, 2016 - 02:37 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

https://en.m.wikipedia.org/wiki/Flyback_converter

I had to look it up.

  • "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
Top
DocJC
DocJC's picture
Level: 10k+ Postman
Joined: Tue. Dec 11, 2007
Posts: 13284 View posts
Location: Cleveland, OH
Posted by DocJC: Fri. May 20, 2016 - 01:55 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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

 

Top
Kartman
Kartman's picture
Level: 10k+ Postman
Joined: Thu. Dec 30, 2004
Posts: 24773 View posts
Location: Melbourne,Australia
Posted by Kartman: Fri. May 20, 2016 - 10:16 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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

Top
Torby
Torby's picture
Level: 10k+ Postman
Joined: Tue. Nov 11, 2003
Posts: 10367 View posts
Location: Bartlesville Oklahoma USA
Posted by Torby: Fri. May 20, 2016 - 12:52 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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. 

Top
Brian Fairchild
Brian Fairchild's picture
Level: Raving Lunatic
Joined: Thu. Oct 18, 2001
Posts: 5358 View posts
Location: Eastern England.
Posted by Brian Fairchild: Fri. May 20, 2016 - 01:07 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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."

Top
ki0bk
ki0bk's picture
Level: Raving Lunatic
Joined: Mon. Sep 8, 2014
Posts: 8400 View posts
Location: Olathe KS
Posted by ki0bk: Fri. May 20, 2016 - 01:07 PM (Reply to #9)
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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"

 

Top
Kas
Kas's picture
Level: Resident
Joined: Sun. Nov 6, 2005
Posts: 709 View posts
Location: Vilnius, Lithuania, Continental EU
Posted by Kas: Sun. May 22, 2016 - 06:33 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

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.

Top