Need simple boost reference

Discussion in 'General Electronics Chat' started by tuuluser, Oct 11, 2013.

  1. tuuluser

    Thread Starter New Member

    Nov 20, 2011
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    I need to add a 15V dc reference voltage to board. I'm going to compare it to some other signals through an ADC for calibration purposes. 20mA would be plenty.

    I only have 12VDC on the rail. I can get a small 2577 boost module on Ebay for less than 3 bucks that will do the step-up, but it takes up a lot of space and is about 15x more power than I need. Seems like overkill.

    Is there a small, low component count way for me to do the step up with an IC?
    Accuracy needs to be about 0.5%.
     
  2. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    You could make a free running boost with a 555, a 2N3904 and an inductor with a zener clamp on the output.

    I made one that boosts 1.5V to 13V, use the same idea.
     
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  3. tuuluser

    Thread Starter New Member

    Nov 20, 2011
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    I like this idea. Only issue is that the most stable rail I have is about 10VDC, so I would have to adjust at least R1 and beef up the zener.

    While looking up the parts on Digikey, I found the LMV431. Looks like this with a couple of resistors might be all that I need. All for less than a buck.
     
  4. tuuluser

    Thread Starter New Member

    Nov 20, 2011
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    0
    The LMV431 won't work, does not boost input voltage.

    Back to bounthunter's tip.
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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  6. #12

    Expert

    Nov 30, 2010
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    Some pre-fab modules:
     
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  7. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Or if you like capacitors.

    If you were just funning about the .5% you can replace the 431 with a zener. :D
     
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