24 V DC to 12/5/3.3 VDC Switching

Discussion in 'The Projects Forum' started by ardyadipta, Nov 6, 2013.

  1. ardyadipta

    Thread Starter New Member

    Nov 6, 2013
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    0
    Hello Guys,

    I would like to make a power distribution board, which receives input of 24Volt DC and gives output of 12V (1A), 5V(2A) and 3.3V(1A).

    I do not want to use regulator such as 7812 or 7805 or Micrel 29150/29300/29500 chips, since they are not too efficient (24V to 5V or 3.3V), and as the result, will make my circuit board hot due to power dissipation.

    Could any of you suggest me circuit design or components for high efficiency switching (above 80%) ?
    I have been searching for it for days,, and nothing satisfied me enough..

    Many thanks!
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
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    To get that efficiency, you must use "buck" switch-mode regulators.
     
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  3. Papabravo

    Expert

    Feb 24, 2006
    10,138
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    On Semiconductor, National, TI, and Linear Technology all have multiple switching regulator chips with easy to follow design guidelines. In the above 80% range you must learn to "grok" inductor fabrication and behavior. This will be followed up by the need for an incredibly competent board layout which can only be acquired by years of experience, and lastly by considerable skill in identifying and procuring low ESR capacitors.

    This will be a challenging project, and if you cannot get suitable components where you reside, will be DOOMED to failure.
     
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  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  5. Papabravo

    Expert

    Feb 24, 2006
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    That is most certainly the case. It might even specify certain critical components by manufacturer and part number, but what do you do if those parts are pure unobtainium where you reside. Any number of posters whine continuously about the difficulty they have obtaining parts. I sympathize with their plight, but short of moving to a different part of the world, they have to get creative by scrounging or synthesizing the parts they need or have available to them.

    Squeezing efficiency above 80% from a SMPS gets progressively more difficult when access to components is limited.
     
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  6. ardyadipta

    Thread Starter New Member

    Nov 6, 2013
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    Thank you so much McGyvr.
    I haven't looked at TI web before..
    this probably the solution..
     
  7. ardyadipta

    Thread Starter New Member

    Nov 6, 2013
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    yeah you are right.. I am trying to look at Digikey also while searching for the design..
     
  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Just to be sure you know, a computer ATX power supply outputs these exact voltages. You can easily convert an ATX power supply to a bench power supply by following some simple instructions - just google "atx power supply to bench" or use this one....

    http://m.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply


    Recycle a power supply from an old computer or buy a new one for $20. All will easily meet your specs.
     
  9. Ramussons

    Active Member

    May 3, 2013
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    OP wanted the voltages from a 24 Volt Input .....

    Ramesh
     
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    With appropriate modification of the input side of an ATX PSU it might be persuaded to run from 24V DC.
     
  11. xxAmritxx

    New Member

    Nov 6, 2013
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    I think there may be a bit of confusion on how i explained it guys.

    So let me just clairfy what im trying to do:

    Mains --> Led Driver --> 42v LED Module --> 12v Fan

    Led Driver:
    Meanwell CEN-100-42
    Data sheet: http://www.meanwell.com/search/cen-100/default.htm
    Input: 240v
    Output: 42v 2.2A

    This is providing power for a LED Module:
    LED requires 2.1A and 42v

    I ALSO need to power a fan.
    Fan requires:
    Input: 12v 0.2A


    How do i power the fan?
    Do I need to get different model driver providing different voltage?

    Do I use a voltage regulator such as this?
    http://www.rapidonline.com/Electronic-Components/1A-Buck-Voltage-Regulators-LM2575-34450
    (I assumed buck regulators were switching regulators, I.E. Non linear and highly efficient ones)

    Or Any other ideas?

    Thanks
     
  12. xxAmritxx

    New Member

    Nov 6, 2013
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    HAHA excuse me on my reply. I was readying wrong thread thinking it was mine. I was so confused at first ahahah!
     
  13. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    Or a multiple output flyback. Or, a buck with "coupled inductor" design. It depends on how tight the load regulation has to be. You can't design a power supply without specs.
     
  14. Ramussons

    Active Member

    May 3, 2013
    557
    92
    It would be simpler to fabricate a new unit than do the required modifications on a ATX PSU :D

    Ramesh
     
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