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Building a PFC for 3KW buck-converter

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Member level 5
Dec 31, 1999
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haymeron pfc

i have got a question !!

Does anybody have some expierience with building a PFC for 3KW buck-converter ???

I am specielly interessed in the three way's to build a PFC !!

I have downloaded all the files from haymeron !!

Thank you


what is your input voltage?
what is the variation of the input voltage?
what is your minimum load current?
what is your output voltage?

regarsd - haymeron

Thanks my friend haymeron for your help !!
But it is better when i learn it on my own, how to build a PFC !!!

But thank you very much my friend for your help !!!!!!


On 2001-08-05 15:54, Vauxdvihl wrote:
Thanks my friend haymeron for your help !!
But it is better when i learn it on my own, how to build a PFC !!!

But thank you very much my friend for your help !!!!!!


you will find new stuf in

regards - haymeron

PFC stand for Power Factor Correction. Power Factor is the ratio of Working Power to Apparent Power.

I have a input of either 1 phase or 2 phase or 3 phase AC 220V input for my 3kW motor drive.
How can I design a circuit to give me some 12v,-12v, and 5, 3.3v for the controller digital power source?

I also need PFC, but for later, I don't understand why the boost circuit increase PF.


Hi ahgu!

If required output power is lower than 150W flyback topology is the best choice.

U can design a multi output flyback by
Unitrode current mode controlers:
UC384X X=2,3,4,5
If ur input mains is 220v UC3844 is The best one.

HI again!

I forgot something:
if required output power is very low then it is recommended a Transformer-Linear Regulator to be used.This is due to problems in realizing a safe and high quality switching power supply particulary multiple output ones.

if u want to design a switching one see POWERINT website.
POWERINT designed some HVICs for offline flyback using them part count lowers while reliability increases very much!!!
in this site u can find alot of data sheet and app. notes as well as design samples.

The link to only brings you to the Texas Intruments site. Unitrode was bought by TI.
But here the link to the Unitrode Design Seminars that has a lot of info on PFC design and theory.
**broken link removed**

Check the following folders for PFC.
slup087 in sem600
slup103 in sem900
slup106 in sem1000
slup093 in sem700
Also do a search at the above link for:

Hope this helps.

Thank u for useful links.
about unitrode :though links to TI.COM a large # of unitrode app.notes is available through TI.COM.@ the page u c :
"TI and Unitrode designers are working together right now to develop next-generation power management solutions. If you're looking for power management ICs or easy-to-design-in products that plug right in, you've come to the right place. Our goal is to be the supplier you look to first for premier power management solutions."

u can find some of them below:
**broken link removed**

also u can find PWM app.notes by :
**broken link removed**

some of them are good for the perpose of house keeping power suply design .(as ahgu asked for them.)
i have designed a well working 120 W offline flyback using UC3844 ,but my usefull references are @!.:smile:

Did someone design PFC circuit build on Vienna bridge?

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