biasing basic question

[geozog86]

Hello! if i have this circuit, my question is "where will this circuit bias itsself (where do the final voltage and current levels depend on) and is it a good choice to creat biasing voltages and currents?" and i have no idea i mean, it's two diode connected transistors, and two mirrors, so it'll end up at some voltage and currents, but why? thank you

 

[haykp]

This is current source scheme. And pretty good one. You can refer to Razavi book for more info about this scheme.
Short circuit description: The lower current mirror copies the current given by the upper current mirror. And the upper PMOS current mirror copies the current given by the lower current mirror.As a result of this the current is very stable of this structure.