DC to DC converter schematic comments and improvements

Discussion in 'The Projects Forum' started by Jorj, Oct 1, 2015.

  1. Jorj

    Thread Starter New Member

    Sep 30, 2015
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    0
    Hello folks, I've created a schematic for DC to DC converter using the isulated converter MGJ2 series by Murata - MGJ2D121505SC with output +15V/-5V
    I'm looking for excelent filtering on the output for lowest possible noise. Please give recommendations/comments of the used values (capacitors, inductors), schematic.
    All values I've taken from dug similar schematics over the web, no formulas whatsoever.
    All electrolytic caps - polymer caps, 20V rating, on the +15V output -> 25V
    All 100nF caps - ceramic MLCC X7R 50V
     
    • dc.pdf
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  2. ronv

    AAC Fanatic!

    Nov 12, 2008
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    1,255
    Hi, Jorj... Welcome.

    You could add an LC filter to the output. Here is a short write up.

    http://www.ti.com/lit/an/sbva012/sbva012.pdf
     
  3. Jorj

    Thread Starter New Member

    Sep 30, 2015
    12
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    In the datasheet it's described more efficient and ... cheaper PI filter.
    Suggested approach requires only 2xCaps at 1uF and 2xChokes 100uH and the switching frequency my converter use is similar (45kHz vs 150khz) so I could use that instead, at least is properly calculated and cheaper, right?
     
  4. ronv

    AAC Fanatic!

    Nov 12, 2008
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    1,255
    You should calculate the inductors and caps for your frequency. They will be larger.
     
  5. Jorj

    Thread Starter New Member

    Sep 30, 2015
    12
    0
    Ok thanks I've changed the values accordingly (low pass filter) at 1Khz, should do the job. 1.png
     
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