diodset.c File Reference

#include "spice.h"
#include <stdio.h>
#include "util.h"
#include "diodefs.h"
#include "distodef.h"
#include "const.h"
#include "sperror.h"
#include "distoext.h"

Include dependency graph for diodset.c:

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Macros
#define	P33   .333333333

Functions
int	DIOdSetup (DIOmodel *model, CKTcircuit *ckt)

Macro Definition Documentation

#define P33   .333333333

Definition at line 17 of file diodset.c.

Function Documentation

int DIOdSetup	(	DIOmodel *	model,
		CKTcircuit *	ckt
	)

Definition at line 20 of file diodset.c.

{
    DIOinstance *here;
    double arg;
    double csat;    /* area-scaled saturation current */
    double czero;
    double czof2;
    double evd;
    double evrev;
    double gd;
    double sarg;
    double vd;      /* current diode voltage */
    double vt;      /* K t / Q */
    double vte;
    double g2,g3;
    double cdiff2,cdiff3;
    double cjunc1,cjunc2,cjunc3;

    /* loop through all the diode models */
    for ( ; model != NULL; model = model->DIOnextModel) {

        /* loop through all the instances of the model */
        for (here = model->DIOinstances; here != NULL;
                here = here->DIOnextInstance) {
            /*
             * this routine loads diodes for dc and transient analyses.
             */

            csat = here->DIOtSatCur; /* includes area dependence */
            vt   = CONSTKoverQ * here->DIOtemp;
            vte  = model->DIOemissionCoeff * vt;
            vd   = *(ckt->CKTrhsOld + here->DIOposPrimeNode) -
                    *(ckt->CKTrhsOld + here->DIOnegNode);

            /*
             *   compute derivatives
             */

            if (vd >= -5*vte) {
                evd = exp(vd/vte);
                gd  = csat*evd/vte + ckt->CKTgmin;
                g2  = 0.5*(gd - ckt->CKTgmin)/vte;
                g3  = P33*g2/vte;
                cdiff2 = g2*model->DIOtransitTime;
                cdiff3 = g3*model->DIOtransitTime;
            } 
            else if (!here->DIOtBrkdwnV || (vd >= -here->DIOtBrkdwnV)) {
                /* off */
                /*
                 * gd  = -csat/vd + ckt->CKTgmin;
                 */
                g2 = 0.0;
                g3 = 0.0;
                cdiff2 = 0.0;
                cdiff3 = 0.0;
            } 
            else {
                /* reverse breakdown */
                /* why using csat instead of breakdowncurrent? */
                evrev = exp(-(here->DIOtBrkdwnV + vd)/vt);
                /*
                 * cd = -csat*(evrev - 1 + here->DIOtBrkdwnV/vt);
                 * gd = csat*evrev/vt;
                 */
                /* should there be a minus here above? */
                g2 = -.5*gd/vt;
                g3 = -P33*g2/vt;
                cdiff2 = 0.0;
                cdiff3 = 0.0;
            }
            /*
             *   junction charge storage elements
             */
            cjunc1 = 0.0;
            cjunc2 = 0.0;
            cjunc3 = 0.0;
            czero = here->DIOtJctCap*here->DIOarea;
            if (czero != 0.0) {
                if (vd < here->DIOtDepCap){
                    arg = 1 - vd/model->DIOjunctionPot;
                    sarg = exp(-model->DIOgradingCoeff*log(arg));
                    /* the expression for depletion charge: 
                     *  model->DIOjunctionPot*czero*
                     *  (1-arg*sarg)/(1-model->DIOgradingCoeff);
                     */
                    cjunc1 = czero*sarg;
                    cjunc2 = .5*cjunc1*model->DIOgradingCoeff/
                        (model->DIOjunctionPot*arg);
                    cjunc3 = P33*cjunc2*(model->DIOgradingCoeff + 1)/
                        (model->DIOjunctionPot*arg);
                } 
                else {
                    czof2 = czero/model->DIOf2;
                    /* depletion charge equation: 
                     *  czero*here->DIOtF1+czof2*
                     *  (model->DIOf3*(vd-here->DIOtDepCap)+
                     *  (model->DIOgradingCoeff/(model->DIOjunctionPot+
                     *  model->DIOjunctionPot))*(vd*vd-here->DIOtDepCap*
                     *  here->DIOtDepCap));
                     */
                    cjunc2 = .5*czof2/
                        model->DIOjunctionPot*model->DIOgradingCoeff;
                }
            } 

            /*
             *   store small-signal parameters
             */
            here->id_x2 = g2;
            here->id_x3 = g3;
            here->cdif_x2 = cdiff2;
            here->cdif_x3 = cdiff3;
            here->cjnc_x2 = cjunc2;
            here->cjnc_x3 = cjunc3;
        }
    }
    return(OK);
}