Electronics > Beginners

Rail splitter circuit (looking for approval :D)

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Marulo:
Hey!

So, I've been trying to make a symmetrical supply from an unsymmetrical for quite some time now, and I think (or at least hope) that I got it!
Problem is, I don't currently have any MOSFETs and ordering them will take some time so I thought, "Why not just ask?".
So I attached the schematic, so please check it out. My train of thought went like this (hopefully you can correct me if I went wrong somewhere):

I can make a normal resistor voltage divider using and buffer it with an op amp, but the problem is, the op amp can't source/sink enough current for, for instance, a modular synthesizer.
So, can I buffer the buffer op amp? I looked online and found a circuit similar to this, briefly simulated it and all seemed good :-+.

Thanks for the help guys!

MrAl:
Hi,

I dont think that is a good idea because both mosfets will be turned on and thus conducting a lot of current.

MarkF:
You should read this thread  https://www.eevblog.com/forum/beginners/virtual-ground-push-pull/msg2343744/#top

Marulo:
Thanks!

I'm guessing I'm mostly interested in this part of the circuit (see attachment).
I know I may sound kinda dumb, but could you explain why using BJTs is better in this situation?

Thanks man! Really helped!  ;D ;D ;D

Zero999:

--- Quote from: MrAl on May 04, 2019, 05:35:30 pm ---Hi,

I dont think that is a good idea because both mosfets will be turned on and thus conducting a lot of current.

--- End quote ---
Actually no, the MOSFETs are configured in class B, not class A.

The problem will be poor transient response, as the op-amp's output will have to change very quickly, when the direction of the output current changes.
--- Quote from: Marulo on May 04, 2019, 06:02:47 pm ---Thanks!

I'm guessing I'm mostly interested in this part of the circuit (see attachment).
I know I may sound kinda dumb, but could you explain why using BJTs is better in this situation?

Thanks man! Really helped!  ;D ;D ;D

--- End quote ---
Better but it's prone to oscillation. Look at the end of the thread linked to by MarkF, for some circuits which have fixed the problem.
https://www.eevblog.com/forum/beginners/virtual-ground-push-pull/msg2374209/#msg2374209

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