help me for this circuit

[fengluan]

look at the circuit above,it's a voltage reference circuit. in my opinion, Vref=Vgsmn1×(R1+R2)/R2,and Vgs=Vth+........ Vth has negative TC and Id has positive TC .

i don't know whether i think is right. and how to analysis it's frequency responce.

 

[yellff]

if the gate voltage of MN2 is high,then the right path has no current.
the result you give is uncorrect,and this time,the MN1 have Vds>Vgs-Vth.
and the gate voltage of MN2 is low,so the result is right

 

[manish12]

VREF≡ SUPPLY VOLTAGE .
PMOS DEP = IS NOT OFF.
NMOS2 ITS GATE = NEARLY CONNECTED TO VDD
NMOS2 = NEARLY ON.
SO VREF=VDD.
PLZ MENTION THE REGION OF OPERATION OF ALL MOS .
YOU SET.

 

[niezimei]

to fengluan, you are right.Vref=Vgsmn1×(R1+R2)/R2.Mdepp here acts as a current source,you don't need to do the the ac analysis actually since it is surely stable.Anyway, if you want to do,break the loop at the gate of Mn2