Above is the basic schematic for a comparator with hysteresis. Determining the values of R1 and R2 is fairly straight forward. They essentially boil down to ratios of R3 and you can just plug the values into the relevant formula.
So, the choice of R3 seems to be the most important design decision. But I haven't really been able to find much information on how to work out what a good value for R3 is.
I've been having some problems with designs that look good on paper but don't seem to function correctly in reality...
Picking a high value seems good, since it would reduce overall current usage. But how high can you go?
What characteristics of the comparator are important? Does the value of VRef have any impact (many comparators have a built in VRef, so you may not have a choice here)?
Essentially my question is: What factors do you need to consider when choosing the value of R3 to design an efficient and stable hysteresis circuit?