+ Post New Thread
Results 1 to 2 of 2
  1. #1
    Newbie level 1
    Points: 18, Level: 1

    Join Date
    Mar 2014
    Posts
    1
    Helped
    0 / 0
    Points
    18
    Level
    1

    Imposed Biasing Problem

    Click image for larger version. 

Name:	photo.JPG 
Views:	8 
Size:	109.2 KB 
ID:	103459

    Hi,

    I've been stuck for hours and I was hoping anyone can help. I'm not even sure how to start the problem. Am I supposed to find the value of the resistor R or find different w/l values for the mosfets? How do I approach the problem? Any help is greatly appreciated. Thanks.

    •   AltAdvertisment

        
       

  2. #2
    Full Member level 2
    Points: 1,771, Level: 9

    Join Date
    May 2010
    Location
    usa
    Posts
    133
    Helped
    29 / 29
    Points
    1,771
    Level
    9

    Re: Imposed Biasing Problem

    Hi Gllster

    Assume all nmos in edge of saturation ---> Vds = Vdsat and let X = W/L, kn = UnCox

    For M3: Vdd - Vss = I3*R3 + Vdsat3 (1)
    X3 = 2*I3/kn * Vdsat3*Vdsat3 (2)
    From (1) and (2) ---> X3

    You can do same thing to find X1 and X2.

    Now from relative of Mx with M1 or M2 or M3 in current mirror --> Ix/I1 = Xx/X1

    And you can find value of R from equation: Vdd - Vss = Ix*R + Vdsx = Ix*R + Vgsx = Ix*R + Vtn + Vdsatx = Ix*R + Vtn + Vdsat1 = Ix*R + Vtn + Vdsat2 = Ix*R + Vtn + Vdsat3

    (Note Vdsat1 = Vdsat2 = Vdsat3 and Vgs = Vtn + Vdsat)

    Note Vdsatx = Vdsat1 = Vdsat2 = Vdsat3



--[[ ]]--