recall a classical MOSFET power supply

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I have revised this classical mosfet AC power supply circuit again,and have making a module block now,Used for serving my series headamps.

this is the original sch scan:
 

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The E102 are they current diodes?

I have begun to wonder why the long tailed pair is not more often used in these kind of comparator scenarions. was actually thinking of doing something for a sine to square converter in a clock with a LTP, simulate at least.
 
The Kubota Reg, uh ?

Nice working reg, but it should deserve some improvements IMHO. Just have a look at this post by Jonathan Carr (and the following posts too) :

http://www.diyaudio.com/forums/showthread.php?postid=135268#post135268

I'm currently willing to implement such regs in my future preamp, and I've made some simulations, trying to improve the output impedance and the line regulation.

For the moment, I ended up replacing the emitter's resistance of the diff pairs by CCS (just a source degerated JFet for example).
Improving the voltage reference filtering with a RC network won't certainly hurt, and adding a decoupling cap for the sensing resistor bridge helps a lot.

I've attached the schematic I've used so far, but I'm sure things can be further improved, though I don't know how... :(

In the schematic, R2/C3/C4 provide low pass filtering for the reference. The C2 cap showed a great influence on the reg's performance (PSRR), the higher being the better...
I've added the C5-C6 caps. I found them mandatory to further reduce the output impedance below 10mOhms.

Feel free to comment/improve/flame...
 

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Yep, sort of...
AFAIK, they provide a lower impedance network, both for the sensing bridge and the whole output, to which it is connected. I didn't invent anything, it appears in many discrete regs, even the Walt Jung's one. Here is a plot of the output impedance, showing that (in theory), it improves the Zo by a 8 factor...
 

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