how to find the voltage gain of this topology

[jimito13]

Hi,i am trying to find the voltage gain of the topology presented in the following picture.I realize that this is a current mirror and i want to use it as a non inverting stage (as we can see the series connection of two inverting amplifiers) to an opamp design.I have searced all over the known bibliography but i cannot find an equation for the voltage gain of this topology...

My second question has to do with the following : Since this topology has two inverting amplifiers connected in series,can we say that the overall voltage gain is the product of the voltage gains of the two inverting stages??That is :

Atotal=A1*A2=[gm1/(gds1+gds2)]*[gm3/(gds3+gds4)]

And my third question is : Is there a general naming for this circuit?

Any helpful answer would be appreciated.Thank you in advance.

 

[FvM]

Atotal=A1*A2=[gm1/(gds1+gds2)]*[gm3/(gds3+gds4)]

You ignored the current mirror. The result is rather
Atotal=A1*A2=[gm1/(gds1+gds2+gm2)]*[gm3/(gds3+gds4)] or
Atotal ≈ gm1/(gds3+gds4)

 

[jimito13]

Thank you very much FvM.I have one more question :

You said that i ignored the current mirror.Can you be more specific?I suppose

A1=gm1/(gds1+gds2+gm2) and not A1=gm1/(gds1+gds2) as i mentioned to my first

post because of the reason you mentioned above?

Thanks again and sorry to disturb.

 

[FvM]

The combination of M1-M3 behave almost similar as a single transistor (regarding gm and gds).
A current mirror adds no gain.

 

[jimito13]

Ok.Clear.Thanks a lot again FvM.

 

[sutapanaki]

May be it will be helpful if you consider what the circuit is doing, namely performing the conversion voltage-current-voltage. The current mirror is not only mirroring the dc current but also the ac one. So, M1 converts Vin to a current i=gm1*Vin. This current gets mirrored into M3 and creates the Vout=i*(ro3||r04)=gm1*(ro3||r04)*Vin
Just another point of view to the same answer given above.

 

[jimito13]

I had something like that in my mind but i was not pretty sure.Thank you very much for your answer.It was very helpful as well