Four-quadrant active output. What is it?

[Rostislav]

Hi, all!

My friends, please, tell me, what is this "four-quadrant active output stage" in high voltage amplifier PZD350A?

http://www.trekinc.com/products/PZD350A.asp

Which is topology and circuit?

Very thanks!!!

[tszaboo]

Source or sink current, positive or negative voltage output.
It is an amplifier, powered by dual rail.

[Rostislav]

Source or sink current, positive or negative voltage output.
It is an amplifier, powered by dual rail.

NANDBlog, very thanks!!!

Ok!

Can whether the classical scheme amplifier (AB class) to replace the four-quadrant topology? Please, see my image. Or no? Maybe other principle work?

[Rostislav]

... dual rail.

NANDBlog,

"Dual rail" - bridge circuit (like on a picture)?

[Rostislav]

Source or sink current, positive or negative voltage output.
It is an amplifier, powered by dual rail.

NANDBlog,
do you have example (schematic) four-quadrant output stage?

Very thanks!

[tszaboo]

... dual rail.

NANDBlog,

"Dual rail" - bridge circuit (like on a picture)?

No, dual rail means that it has an internal positive and negative power supply.
It could be a bridged circuit also, like the one you draw, becuase it can output negative voltage on the output therminals. Well, I mean the voltage between the two terminals can change polarity.

[macboy]

Source or sink current, positive or negative voltage output.
It is an amplifier, powered by dual rail.

NANDBlog, very thanks!!!

Ok!

Can whether the classical scheme amplifier (AB class) to replace the four-quadrant topology? Please, see my image. Or no? Maybe other principle work?

Yes, an audio power amplifier (or any op-amp) is an example of a four quadrant output device.

[bson]

what is this "four-quadrant active output stage"

It means it can sink current during the positive phase - for example when faced with a reactive load that lags - and similarly source current during the negative phase.  It's a fancy way of saying "negative feedback amplifier".

[TimFox]

The "quadrants" in question are the four quadrants of a graph of output voltage vs. output current.

[woodchips]

Yes, the first quadrant is +V and +I so the output will source a current flowing out to a +ve voltage. Similarly the third quadrant is -V and -I so the output will source a current flowing out to a -ve voltage.

The other two quadrants are the tricky ones.

Quadrant 2 is +V and -I, so the output has to sink current flowing into the output from a +ve voltage.

Similarly quadrant 4 is -V and +I, so the output has to sink a current flowing into the output from a -ve voltage.

What you need is a push pull transistor pair connected between 0V and +ve power rail and the same from 0V to the -ve power rail, with the emitters all joined together. It isn't as simple as just an op-amp output, probably need steering diodes to stop transistors turning on when they shouldn't.

Think of it as a supply of +ve voltage, if the output voltage is lower than what is desired then source current. BUT if the output voltage is HIGHER than the desired voltage then it has to sink it. Similar argument for -ve voltage.

[kridri]

Source or sink current, positive or negative voltage output.
It is an amplifier, powered by dual rail.

NANDBlog,
do you have example (schematic) four-quadrant output stage?

Very thanks!

The  HP 6826A is an older bipolar/ four quadrant power supply from which you can have the schematics with detailed description. Other know four quadrant supplies are from Keithley but to my knowledge the schematics aren't for download.

http://literature.cdn.keysight.com/litweb/pdf/05950-1702.pdf?id=1415976

[ivaylo]

Yes, the Keithley or Keysight SMUs do it. Also these -  http://www.kepcopower.com/bop.htm