DC-DC converter

Discussion in 'General Electronics Chat' started by NUNOMATTA, Dec 26, 2013.

  1. NUNOMATTA

    Thread Starter New Member

    Jul 18, 2010
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    I'm trying to build a small inexpensive converter 12VDC to 24 VDC @ 1.5 to 2.0 Amps.
    The MC33063A looks like a good option, but I'll appreciate any ideas and comments.
    NSM
     
  2. ian field

    Distinguished Member

    Oct 27, 2012
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    There are various online and downloadable calculators that work out the component & inductor values, but 1.5A is about the limit for a 34063 unless you use an external transistor to boost it.
     
  3. NUNOMATTA

    Thread Starter New Member

    Jul 18, 2010
    2
    0
    Thanks' Ian,
    I'm looking for these calculators, but I didn't had much luck so far.
    Anyway, I retested my 24Volt users, and they peak at 850mA, so I don't need to add any components to the 33063.
    Wish me luck.
    Regards,
    NSM
     
  4. ian field

    Distinguished Member

    Oct 27, 2012
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  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    You probably still do. :)

    A 34063 in boost 12v->24v will run about 75% efficiency at best. So to get 24v 0.85A output requires 12v 2.26A input.

    You need a switching device good for 2.26A average at least. Probably a device with a low ON resistance at 5A would be best.
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
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    IIRC, there's some more info in the 78S40 appnote from Motorola/On-Semi. Its basically the same regulator with a few extra bits in the package.
     
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