"elucidate"?..... must have found it on a bubble gum wrapper in times past.
With these supplies, they need a current flowing in the transformer circuit all the time, so they need a minimum load, or the book keeping part has no knowledge of whats going on, and so can't make sensible decisions. This is done by a big resistor on the output that just soaks up current, and keeps the pwm working into a load, some of that load (tiny )can also be in the divider. Too high an impedance and noise can occur in the feedback loop, and instability is the result.
In the series of these I played with, they use a zener in series with the divider, so the currents are probably not what you expected.
The slope of the gain of the comparator is set in a feedback loop at the pwm chip, so is not likely effected....
The clincher is that they give you a trim pot to modify the voltage .... so they don't consider this an issue either if you think about it.
Adam,
I was thinking slightly higher setting ability, because we don't know the slope of the comparator. It may ease off a bit fast as it gets close to Vmax, so if you want to push it hard in equalise to stir up the electrolyte, a bit of headroom may be useful to frighten em a bit ... or not. You'll know when you try it... or try it at home.
Just figure if your burning fuel to charge , you don't want to see half an amp for the last hour etc.... But testing is knowing.
Anyway it is easy to change as we have seen.
.................oztules
