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DownSW
Joined: 20 Jan 2005
Posts: 11
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 20 Jan 2005 15:16 Did anyone help me design a 220V - 3.3V (15A) flyback? |
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I try to make a flyback power supply for my matrix display. I used PC power supply before but it's too big and complex. I want a small . I have a lot of old PC AT/ATX. Can I h(at)ck them? (At least, I can take some component).
I will draw some shematic to post soon.
But I confused about the equation to estimate Flyback Transformer.
It will two output:
- 5V, 500mA
- 3.3V,
May anyone give me an ideal to start?
Thank you for read!
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DownSW
Joined: 20 Jan 2005
Posts: 11
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| 21 Jan 2005 12:13 Some more... |
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Hic, but it must be supply with an ATX Power[/img]
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IanP
Joined: 05 Oct 2004
Posts: 6268
Helped: 1457
Location: West Coast
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| 21 Jan 2005 13:19 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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Is it really 15A?
In this case I woud suggest that you use one of your AT power supplies and step down 5V to 3.3V. There are several options here, but first you have to decide whether you like this option or not.
Building 220ac/3.3dc flyback PS may be not easy task..
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kekon
Joined: 19 Sep 2002
Posts: 100
Helped: 1
Location: Poland, Białystok
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| 21 Jan 2005 19:56 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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| The task is not as difficult as it seems. I have some experience with building flyback converters up to 150W so I would use flyback smps to power that LED matrix.
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VVV
Joined: 26 Nov 2004
Posts: 1379
Helped: 253
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| 22 Jan 2005 8:10 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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| If the current is really 15A at 3.3V, I would go with a forward converter. If you have PC power supplies, you should be able to put something together, using the transformers and chokes in them. It's mostly a matter of changing the output voltage, which can be as simple as changing a resistor or two. The only concern I have is the startup/ bootstrap circuitry, but most likely it will work, even with 3.3V output.
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rauol
Joined: 02 Oct 2002
Posts: 342
Helped: 11
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| 22 Jan 2005 11:28 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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Now a days PC power supplies also have a 3.3 V power supply.
Building a high current low voltage power supply is not advisable as the ripple current and peak current on the output capacitor and diode will be very high. try forward converter using standard UC 3843 controllers.
Again with a direct 3.3 volt SMPS (flyback or forward) the transient response will be sllugish and if u are using it far a high speed Microcontroller Etc it is better u use a 5 Volt supply and use a Step down controller to make 3.3 volt.
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DownSW
Joined: 20 Jan 2005
Posts: 11
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| 24 Jan 2005 8:03 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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Thank all of you for support.
This is small one. The current of this board is vary from 3-5A. But I need the power supply for bigger one.
I have collect some useful document that show me how to make Flyback and Forward Power now. I will try both. When I have some thing to show i will show it here.
I came from Vietnam. My country have lack electronic component. I will try to take some from old and failed power supply.
I will load one of useful document here (because i lost the link)
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DownSW
Joined: 20 Jan 2005
Posts: 11
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| 31 Jan 2005 9:53 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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This is the shematic.
Any suppose for improvement?
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IanP
Joined: 05 Oct 2004
Posts: 6268
Helped: 1457
Location: West Coast
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| 31 Jan 2005 10:18 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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| For 3.3V output voltage you will have to redesign the leedback circuit with opoisolator. You have there 5Vzener diode which should be removed (together with 10kΩ bias resistor) and the emiter goes straight to -V (in your case it will be 0V)..
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VVV
Joined: 26 Nov 2004
Posts: 1379
Helped: 253
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| 01 Feb 2005 20:47 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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I only looked at the schematic and I think the primary of the transformer should be reversed. Other than that, it seems OK.
With a MOSFET you do not necessarily need R8, D1, C6, but they will not hurt.
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masoudk_81
Joined: 02 Jan 2005
Posts: 23
Helped: 4
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| 14 Feb 2005 14:53 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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Hi
you can use TOP Switches such as TOP222. you can find it's datasheet online.
it is so easy to implement ans has switch, controller and compensator
inside it together.
masoud
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omore
Joined: 25 Oct 2005
Posts: 77
Helped: 7
Location: Argentina
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| 28 Oct 2005 2:49 Re: Did anyone help me design a 220V - 3.3V (15A) flyback? |
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If you need further help let me know.
Do not recomend use TOP 221 - 226 series as the manufacturer ( Power Integration ) does not recomend that, althought if you only wish to construct few devices it will work. I´m manufacturing SMPS using TOP225 and they work fine.
Consider to visit www.powerint.com there you will find a lot of App. notes, schematics and PCB layouts. If U have little experience with SMPS and wish to not expend a lot of time their PCB layouts will help U to get your Power Supply running sooner.
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faorozco
Joined: 17 Jul 2006
Posts: 5
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| 17 Oct 2006 22:16 Did anyone help me design a 220V - 3.3V (15A) flyback? |
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| DownSW thats a great matrix display panel, would you help me with the schematics?
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rachid77
Joined: 24 Jun 2006
Posts: 11
Helped: 2
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| 24 Oct 2006 0:00 |
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please help me with the schematics???
regards.
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paps09
Joined: 01 Oct 2007
Posts: 6
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| 12 May 2008 8:11 Did anyone help me design a 220V - 3.3V (15A) flyback? |
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Wow... Nice LED Display...
Why dont u like to share some tech. detail abt it. 
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