I am not sure I get the reason behind doing that since all "the magic parts" would be different.
I was realising this, so it couldn't even be a corruption of the _Ghurd-Controller_
![Cool 8)](https://www.fieldlines.com/Smileys/default/cool.gif)
, in this instance it is no longer a personal pronoun, it is a product and idea all to itself.... Feel sorry for the guy whos name is Xantrex.
In my circuit, the right hand side, from the 2N7000 to the 'output to fet gates', is sort of to get sharp switching and high voltage (above logic level voltages) to the power fet gates.
It is sort of ghurd's version of Darlington-izing mosfets to get the power fet gates up to >12V instead of <5.1V.
Might look for a simpler opamp / comparator circuit with feedback... something that uses a Zener instead of 7805.
If I understand a little of the operation of your circuit, it was that due to the small hysteresis and sharp cutoff, the switiching effect was akin to PWM, in that it is of a high frequency, is this correct?
When I looked at using a zener, all the info and expert-opinions were that zeners have way too much temperature drift, are unreliable off the shelf (voltage wise), and especially bad down the low end, 4.7/5/8V.
Personally it is what I wanted to use, so if the temperature stability is in reality a non issue, then the inter item voltage variance becomes a non issue, as the o/p needs to be calibrated anyway. Is there any reason why two 100k pots in parallel with the zener would not work, and for example with a 14V supply and say a 20K series resistor?
I am not sure I fully understand how feedback on opamps work to create hysteresis, something to learn and play with I guess... but sounds like the promise of one vRef, and one comparator/opamp.
The other issue with zeners is: Are they easily scavangeable? A LM7805 etc. is probably more common in day to day stuff... its a funny design spec, scavengability.
Many DIY circuits I tried years ago had stablity issues related to duty cycle or temperature swings. Close enough to be good enough for something made from salvaged parts.
Not sure what parts caused it, I just know it happened. Pots, Zeners and ICs often are effected.
But is close enough good enough? I tried various combinations of things in LTspice with temperature step, and it thinks it is the opamps that are the worst... nothing like the realworld tho.
Cheers.