Comparator Implementation with VCVS

Discussion in 'Programmer's Corner' started by RedKing, Nov 17, 2009.

  1. RedKing

    Thread Starter New Member

    Nov 5, 2009

    I am currently trying to simulate an oscillator circuit using PSpice. I have been recommended to use a Voltage Controlled Voltage Source in lieu of a comparator, due to its more ideal characteristics (since I can't find a model for the one I need). I need to implement this as part of a bigger circuit, however. Ultimately, this is supposed to be an Inverting Comparator with Hysteresis. It is modeled by a piecewise linear VCVS:

    Compar.sp Inverting Comparator with Hysteresis
    .PARAM vohigh=5v volow=-2.5v rbval=1k rfval=9k
    Ecomp out 0 PWL(1) a b -2u,vohigh 1u, volow
    Rb b 0 rbval
    Rf b out rfval
    Cb b 0 1ff
    Vin a 0 PWL(0,-4 1u,4 2u,-4)
    .TRAN .1n 2u
    .PROBE Vin=V(a) Vab=V(a,b) Vout=V(out)

    Where: Vreference_low = (Vo_low*Rb)/(Rb + Rf)
    Vreference_high = (Vo_high*Rb)/(Rb + Rf)

    When Vin exceeds Vrefhigh, the output Vout goes to Volow. For Vin less than Vreflow, the output goes to Vohigh.

    I'll admit; I'm quite inexperienced with using PSpice and have only implemented designs using the OrCad GUI. I would really appreciate some help on this problem.

    Pretty please?