-48VDC to +12VDC output

Discussion in 'The Projects Forum' started by ajay_jamdar, Sep 14, 2013.

  1. ajay_jamdar

    Thread Starter New Member

    Sep 14, 2013
    2
    0
    Hello,
    I am working on project where i am getting -48VDC from battery & my circuit works on +12VDC/1.5Amp.
    Please suggest me circuit/convertor to get +12VDC from -48VDC.
     
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,857
    767
    It's strange that the -48VDC from battery, why not 48Vdc?
    You may buy a product, or you can using LM3763 to DIY and adjust the voltage to 12V from 48V.
    LT3763 - 60V High Current Step-Down LED Driver Controller.
     
    ajay_jamdar likes this.
  3. ajay_jamdar

    Thread Starter New Member

    Sep 14, 2013
    2
    0
    It is cell site, can you tell me the correction/modification that how i can get +ve volt from -ve volt. Simple in rectifire circuit.?
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    -48 volt hmm.. You do not plan to tap of your telephone line. Because that is bad idea
     
  5. ScottWang

    Moderator

    Aug 23, 2012
    4,857
    767
    Because we need to avoid the bad thing happened, so do you have the picture and more infos about your battery?
     
  6. vk6zgo

    Active Member

    Jul 21, 2012
    677
    85
    -48vdc is a very common power supply voltage in Telephone Exchanges & the like.

    Many such sites also have a protected 240vac source,so if you don't have to have continuous power & can handle a very short break,it may be an easy answer to simply run it off a Mains operated power supply.

    If not,& the circuit is not already built up into a case,you can simply invert it,so that the positive side of the circuit goes to the Earth rail,& the negative side is driven via a -12V regulator.

    This is how many manufacturers adapted their products to different supply polarities in the days before switchmode circuits which can be used for polarity inversion were available.

    Signal earths should still work OK,as the power circuit will have quite a low impedance to signal frequencies.
     
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