Improving the linearity of an N-ch MOSFET output stage

it is amazing

the whole picture which you post above is a follower, isn't it. just like
common drain circuit (emmiter follower) .
so if i want to build a amplifier with this circuit, i must add input and VAS circuit. is what i think correct?

and another question. i only have irfp240 , so how should i do this circuit beacause of zvp3310 bias problem. i can not connect gate of zvp3310 to output directly. give me detailed resolution, pls.
 
Re: it is amazing

john-china said:
the whole picture which you post above is a follower, isn't it. just like
common drain circuit (emmiter follower) .
so if i want to build a amplifier with this circuit, i must add input and VAS circuit. is what i think correct?

Yes, that is correct.

john-china said:
and another question. i only have irfp240 , so how should i do this circuit beacause of zvp3310 bias problem. i can not connect gate of zvp3310 to output directly. give me detailed resolution, pls.

You can not use this particular circuit with irfp240 - only Logic Level N-ch MOSFETs will work (i.e. IRL540 or 2SK1530 etc.). For IRFP240 you would need to change the arrangement to include an additional bias for P-ch device. I did not try it so I can not offer you a ready circuit for that. It should be possible, thought. One more thing about using IRFP240 - you'll lose much more voltage out of the supply rails , the current source would need a boosted (by 5-10V) separate supply and the temperature compensation needs to be be different.

Overall - it is not easy to replace the o/p devices here for "non LL", sorry. Look for IRL540 - they are quite common and cheap - and good for up to about 50W output per pair.

Cheers

Alex
 
A Nice Tweak from N-Channeler

To use that circuit with Standard Gate drive Vertical N-channel Mosfets/Igbts

Here is an enhancement[a nice tweak]:)

which will also offer rail to rail performance as an added bonus!!
 

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Nelson,

would you mind to share some bread crumbs why this is the case (that is, as far as you have determined the root causes)?

Has it to do with a closer to ideal quadratic transfer function in general, or is it a distortion cancelling "load line trick" that works better with them?

- Klaus
 
However, privileged electrical conditions are needed for any device to exhibit the lowest possible modulations of their parameters, but in case of SiC the main advantage is in the material itself that on the same working temperatures is much better than other known semiconductors. SiC BJTs are also very promising. You can't eliminate current modulation effects when the load is complex, but they can be minimized by topology and better devices used.
 
Alex,
accomplishing several things in one blow sometimes mean compromising. The task of a phase splitting stage is to generate two balanced differential signals, most importantly, being accurately 180° out of phase and equal in amplitude. The gate-source and gate-drain properties are not equal. To noticeably linearize the output devices, the CFP could be a way to go.

Klaus,
that`s a nice circuit in post #18, when M5/M6 JFET, M3/M4 bipolar.
 
I am happy to invite forum members to have a look at my short article:

http://www.ant-audio.co.uk/Theory/N-channel D-MOSFET output stage with improved linearity.pdf

In this thread I will try to answer questions about that circuit configuration and also about the last diagram from the article - a practical example of an output stage that can be used with or without an overall NFB with either tube or solid-state VAS. I attach this circuit diagram here as well.

Alex Nikitin

I have found this URL about an additional distortion removal circuit
Distortion removal circuit
Here the automatic translation in English
Google Übersetzer

what do you think about this topology?
 
I am happy to invite forum members to have a look at my short article:
http://www.ant-audio.co.uk/Theory/N-channel D-MOSFET output stage with improved linearity.pdf
In this thread I will try to answer questions about that circuit configuration and also about the last diagram from the article - a practical example of an output stage that can be used with or without an overall NFB with either tube or solid-state VAS. I attach this circuit diagram here as well.
Alex Nikitin

Which commercial brands (except Creek) uses this topology?