Implementing dead time without a DSP

Thread Starter

umphrey

Joined Dec 1, 2012
39
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.
 

THE_RB

Joined Feb 11, 2008
5,438
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). :)
 
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