Push pull regulators

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#2
Think of it as a plain ordinary audio amplifier whose frequency response goes all the way down to DC (zero Hertz). The amplifier's input is a reference voltage, derived from a Zener diode or an LM329 or a string of LEDs. The input is multiplied by the closed loop gain of the amplifier, and then presented at the output. If for example the reference voltage is 6.90V {LM329} and if the closed loop gain is 6.745dB (2.174x), then the output is 6.90 * 2.174 = 15.00 volts DC.

Just like 90% of all other audio amplifiers, this one has a push pull output stage. Other designers have made working push pull amplifiers that function extremely well, and I expect that you can too! Give it a try and have some DIY fun.
 
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#3
I call them "tandem regulators", and properly implemented, they can have outstanding performances:
Elvee

Post in thread 'I am clearing my attic: here is the legacy thread'

Tandem regulators

Series and shunt regulators can be associated in order to improve some performances. They are generally known as two-quadrant regulators, and the main goal is usually the improvement of dynamic performances: a classical series regulator, having to deliver an output anywhere between 0 and Imax demands difficult tradeoffs regarding the compensation.
It has to remain stable and well-behaved, despite the huge variation of the ballast's transconductance induced by the current change, and it has to deal with many types of loads, including purely capacitive ones.
To...
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They can also be used as amplifiers:
Elvee

Thread 'Tandem-based amplifiers'

Tandem regulators are a special class of two-quadrant regulators, in which the series and shunt members do not simply work side-by-side, but cooperate in an active, synergetic manner to sublimate the performances.
I have given details about the principles here (many other topologies are possible, but for the amplifier I will concentrate on a particular one):

TandemD.png


These circuits not only work superbly as normal regulators, but thanks to their stiff, accurate output and their source/sink ability, they also do wonders in virtual ground generation

This begs the question...
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Elvee

Thread 'TandyMOS is not your typical amplifier:'

It has no diff-pair input, no DC-servo (yet its DC offset is negligible), no complementary output, no adjustments (yet its quiescent current is stable and deterministic), it uses ordinary vertical enhancement NMOS having a normal threshold voltage, yet it is free from the output swing limitations normally associated with such devices. The topology is half non-switching, half class AB and inverting.
In short: an oddity.
It is based on the Tandem topology, which has been evoked here...
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#4
I am very interested in a virtual ground because I design an octo microphone preamplifier where I only use positive regulators.

A positive 32 volt regulator with virtual ground to make -16 0 +16 and a 48 volt for 0 +48.
The preamp is fully differential so draws very little on the virtual ground which is simply made of a 1/2 NE5532.
Both regulators are positive, same topology based on TL431.
 
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