Implementing dead time without a DSP

Discussion in 'General Electronics Chat' started by umphrey, Sep 11, 2013.

  1. umphrey

    Thread Starter Member

    Dec 1, 2012
    Hello all,

    I am thinking about attempting a solar inverter build without a DSP. To be more specific, I plan to have 2 square wave signals coming out of a comparator that are the inverse of each other, and I need to implement some circuitry to ensure that they are not going to be logic true at the same time.

    Do I really need it? The system will be low voltage (10-20VDC) and low current (100mA-4A). I plan to use FETs, which I don't think are quite as sensitive. Furthermore, the solar cells can be short circuited without damaging them. However, there may be a low resistance 12V battery that could potentially get shorted.
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
    Hard to say. Maybe you could post your proposed schematic so we would have a better idea.
  3. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    The standard way to do that in analogue (with opamps etc) is to have an initial "square wave" waveform with sloping edges, the rate of the slope determines the dead time.

    Then you use two comparator circuits, to trigger the two HI outputs. Assuming a 10v "square wave" as the input;
    comparator 1; output is HI only when input >7v
    comparator 2; output is HI only when input <3v

    Since they are driven from ONE input waveform, both outputs cannot be HI at the same time, and the dead time delay between either output going HI is the time the sloping edge takes to go from 3v to 7v (or vice versa). :)
    #12 likes this.