transcendent
Newbie level 4
Having some trouble here. I have simulated a mosfet potential divider in HSPICE given some simplified MOSFET parameters for pmos and nmos. The widths have been prechosen, as is Vdd and Vss.
Key parameters known:
Vdd = 5V
Vss = -5V
Kn = 50u Vt = 0.9
Kp = 18u Vt = -0.6
Current is unknown.
Vgs is unknown
As said: width and length are indeed known.
**broken link removed**
This is essentially the circuit (c). Except that it isn't ground at the bottom. Instead Vss = -5V.
So I ran through spice, which can indeed give simulated Vout (Vref) and the current going through both mosfets and Vgs values.
I can't figure out for the life of me how to extract Vref with the parameters given however.
Id = beta (Vgs - Vt)^2
beta = K/2(W/L)
Tried equating current: beta1 (Vgs1 - Vt1)^2 = beta2 (Vgs2 - Vt2)^2
Still left with unknown Vgs.
Also note, the place i got that diagram says:
**broken link removed**
However, I can't work out how this is derived (including Vss instead of ground)
Key parameters known:
Vdd = 5V
Vss = -5V
Kn = 50u Vt = 0.9
Kp = 18u Vt = -0.6
Current is unknown.
Vgs is unknown
As said: width and length are indeed known.
**broken link removed**
This is essentially the circuit (c). Except that it isn't ground at the bottom. Instead Vss = -5V.
So I ran through spice, which can indeed give simulated Vout (Vref) and the current going through both mosfets and Vgs values.
I can't figure out for the life of me how to extract Vref with the parameters given however.
Id = beta (Vgs - Vt)^2
beta = K/2(W/L)
Tried equating current: beta1 (Vgs1 - Vt1)^2 = beta2 (Vgs2 - Vt2)^2
Still left with unknown Vgs.
Also note, the place i got that diagram says:
**broken link removed**
However, I can't work out how this is derived (including Vss instead of ground)
Last edited: