Current mirror - stacked pairs of NPN

[Prototyp_V1.0]

Hi.

Reading this thread, I found a sort of current mirror.

I've uploaded a cropped version of the circuit in the referred thread.

What I don't quite understand is the working of the circuit. Is this circuit expected to have better characteristics than a circuit with only two NPN's?

thanks

 

[dick_freebird]

This is a piece of something bigger, it looks like a PTAT
or an attempt to produce a tempco that differs from
the bias current. The key is VBE vs VBE+I*R at the
bottom, the rest is just cascode shields.

 

[leo_o2]

VBE_Q810=VBE_Q800+I*R
VBE_Q810-VBE_Q800=VT*ln4 if they have matched current.
A current mirror is needed at the high end.

 

[Prototyp_V1.0]

VBE_Q810=VBE_Q800+I*R
VBE_Q810-VBE_Q800=VT*ln4 if they have matched current.
A current mirror is needed at the high end.

I understand that as that circuit alone isn't useful for anything?