Voltage Multiplier for battery monitor

Discussion in 'The Projects Forum' started by SkyBill, Mar 6, 2010.

  1. SkyBill

    Thread Starter New Member

    Feb 11, 2010
    I built several LED bar graphs to display the voltage of each LiFePO4 cell in a series of 8. It is critical that the voltage does not drop below 2.5V for these batteries. The thread for that project is http://forum.allaboutcircuits.com/showthread.php?t=34266&highlight=lm3914.

    I was going to use a common 12V power supply for each display but I just realized that won't work since all the grounds have to be common and with the cells all in series it would short out the batteries.

    I need to use the 2.5V -3.5V cell to power each circuit but the voltage is too low for the LM3914 IC. I need to boost the 2.5V - 3.5V to greater than 6V to power the circuit. The MAX756 IC looked perfect but only goes to 5V and that is just a little too low.

    Diagram explaining the situation is attached.

    Any suggestions? Thanks for the help.
    Last edited: Mar 6, 2010