LED Bar graph on 48volts

Discussion in 'General Electronics Chat' started by CDtech026, Jun 18, 2007.

  1. CDtech026

    Thread Starter New Member

    Jun 18, 2007
    3
    0
    i need to create a circuit using the LM3914 chip that will monitor a set of 4 batteries with a voltage range from 46 to 56 volts. id like each led to represent 1 volt with the chip set in bar mode. anyone think they can help?
     
  2. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    Show us what you have so far.
     
  3. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    If it were me, to keep it simple I'd use something to drop a constant 46 volts from the monitored Bat voltage, then send the result to the voltage divider network going to the input of the LM3914.
    Think.... "Zener"......
    Perhaps a little over voltage and reverse voltage protection also to that input if the batterys are constantly being changed etc.
     
  4. CDtech026

    Thread Starter New Member

    Jun 18, 2007
    3
    0
    http://usera.imagecave.com/bloodlust/48volts.JPG

    Thats what i have so far but that will only work with less than 30 something volts because of the regulator limits. Would a voltage divider before the regulator work even though the load on the divider changes with each LED thats lit?

    EDIT : I forgot to draw that i have pin 9 wired to pin 3 putting the chip in bar mode, which is necessary for my application. I also have a separate regular supplying the LEDs with 5 volts and a set of (10) 2N3906 transistors between the LED grounds and the chip to keep the LED drive current out of the chip.
     
  5. CDtech026

    Thread Starter New Member

    Jun 18, 2007
    3
    0
    im thinking a 1N4755. anyone agree?
     
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