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Voltage boosting an opamp

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Yansi:
Hello!

Just got me thinking... For some project I might need a precision DC voltage source controlled via a DAC. The problem is I need 4 quadrant operation - so opamp is the obvious solution. The voltage we are talking about might be say few +5V downto -50V, output current 1mA is more than enough, BW not critical, 1kHz very well sufficient.

The problem is, for +5-50V output I'd need an opamp designed for at least 60V supply operation. I know that some high voltage opamps do exist, but mostly expensive. I'd like to try to stick with jellybean parts for this, not afraid the component count will be a little higher. Only if that fails, I'll buy a high voltage opamp for this :-)

Do you have any suggestions, how to voltage boost the output of an opamp?

One of my first ideas was to ground the output of the opamp through a rather small impedance and then to use a pair of current mirrors in the opamp supply rails, to control the output voltage.
I have drawn my idea, please see below. Does it stand a chance to work?  I think it just might, but I may well be mistaken. 

Thank you for ideas as always!
Yansi

//EDIT: Just found this voltage booster (the second image below). Almost exact schematic! Thats pleasing I have reinvented the wheel and it might work just fine. Also interesting to note the local feedback through R1 C1.
Still I do not get the purpose of matching/pairing the trannies in here. What will the assymetry cause? I can't figure out.

f5r5e5d:
http://www.linear.com/product/LTC6090 is a bargain at $5 if you value your time at all

Yansi:
$5 is not bargain. I can make at least 5 of those circuits above  for $5, with the same result. Sorry.

And btw, the availability of LTC6090 at local major distributors is exactly zero.

KhronX:
That second schematic makes a lot more sense - i was wondering where the opamp's output was going to (or how it was working at all), in the hand-drawn one :)

Yansi:
After a few (two or three?) hours of breadboarding, I would  prefer using a common base gain stage used for this purpose, instead of this fiddly crazy supply current sensing topology. I couldn't manage it to work good enough if at all.  The common base gain stage works more than good enough, however for AC signals, I'd be very afraid of significant crossover distortion.  :-//
This time I just need to amplify a slowly varying DC signal.

Now just only current limiting to be  added to that circuit.

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