type 3 compensation for VMC (LTSPICE)

Discussion in 'General Electronics Chat' started by chimera, Apr 24, 2013.

  1. chimera

    Thread Starter Member

    Oct 21, 2010
    122
    2
    Hey guys. I have attached an .sch file in which Im modeling the small signal analysis of a type III compensator. I have also attached the output which Im measuring.

    The op amp Ive modeled is TLC2272 and I have a compensation loop around it.

    Who ever is looking at this file, make sure that when you simulate it, add the following trace in the simulation window: V(vcont)-V(n002). This will give you the actual phase and gain margin plot which a type 3 should provide.

    Im having a little difficulty in understanding as to why my phase does not start from -90deg. Rather, its starts from +90 and although thats fine as the max phase delay the compensation can add is -180 (which would yield 360 phase shift total when combined with the phase shift added by the negative feedback)

    Thanks!
     
  2. chimera

    Thread Starter Member

    Oct 21, 2010
    122
    2
    no go folks??
     
  3. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    I'd help if I were an LTSpice user.
     
    chimera likes this.
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