Add SOA-check for collector-substrate diode (model parameter bvsub)

src/spicelib/devices/vbic/vbic.c

@@ -185,6 +185,8 @@ IFparm VBICmPTable[] = { /* model parameters */
  IOPR("bvbc", VBIC_MOD_VBC_MAX, IF_REAL, "maximum voltage B-C junction"),
  IOP("vce_max", VBIC_MOD_VCE_MAX, IF_REAL, "maximum voltage C-E branch"),
  IOPR("bvce", VBIC_MOD_VCE_MAX, IF_REAL, "maximum voltage C-E branch"),
+ IOP("vsub_max", VBIC_MOD_VSUB_MAX, IF_REAL, "maximum voltage C-substrate branch"),
+ IOPR("bvsub", VBIC_MOD_VSUB_MAX, IF_REAL, "maximum voltage C-substrate branch"),
  IOP("selft", VBIC_MOD_SELFT, IF_INTEGER, "0: self-heating off, 1: self-heating on")
 };
 

src/spicelib/devices/vbic/vbicdefs.h

@@ -485,6 +485,7 @@ typedef struct sVBICmodel {           /* model structure for a vbic */
     double VBICvbeMax; /* maximum voltage over B-E junction */
     double VBICvbcMax; /* maximum voltage over B-C junction */
     double VBICvceMax; /* maximum voltage over C-E branch */
+    double VBICvsubMax; /* maximum voltage over C-substrate branch */
 
     unsigned VBICtnomGiven : 1;
     unsigned VBICextCollResistGiven : 1;
@@ -600,6 +601,7 @@ typedef struct sVBICmodel {           /* model structure for a vbic */
     unsigned VBICvbeMaxGiven : 1;
     unsigned VBICvbcMaxGiven : 1;
     unsigned VBICvceMaxGiven : 1;
+    unsigned VBICvsubMaxGiven : 1;
 } VBICmodel;
 
 #ifndef NPN
@@ -736,6 +738,7 @@ enum {
     VBIC_MOD_VBE_MAX,
     VBIC_MOD_VBC_MAX,
     VBIC_MOD_VCE_MAX,
+    VBIC_MOD_VSUB_MAX,
     VBIC_MOD_SELFT,
 };
 

src/spicelib/devices/vbic/vbicmask.c

@@ -363,6 +363,9 @@ VBICmAsk(CKTcircuit *ckt, GENmodel *instPtr, int which, IFvalue *value)
         case VBIC_MOD_VCE_MAX:
             value->rValue = here->VBICvceMax;
             return(OK);
+        case VBIC_MOD_VSUB_MAX:
+            value->rValue = here->VBICvsubMax;
+            return(OK);
         case VBIC_MOD_TYPE:
             if (here->VBICtype == NPN)
                 value->sValue = "npn";

src/spicelib/devices/vbic/vbicmpar.c

@@ -509,6 +509,10 @@ VBICmParam(int param, IFvalue *value, GENmodel *inModel)
             mods->VBICvceMax = value->rValue;
             mods->VBICvceMaxGiven = TRUE;
             break;
+        case VBIC_MOD_VSUB_MAX:
+            mods->VBICvsubMax = value->rValue;
+            mods->VBICvsubMaxGiven = TRUE;
+            break;
         case VBIC_MOD_SELFT:
             mods->VBICselft = value->iValue;
             mods->VBICselftGiven = TRUE;

src/spicelib/devices/vbic/vbicsoachk.c

@@ -17,14 +17,15 @@ VBICsoaCheck(CKTcircuit *ckt, GENmodel *inModel)
 {
     VBICmodel *model = (VBICmodel *) inModel;
     VBICinstance *here;
-    double vbe, vbc, vce;    /* actual bjt voltages */
+    double vbe, vbc, vce, vsub;    /* actual bjt voltages */
     int maxwarns;
-    static int warns_vbe = 0, warns_vbc = 0, warns_vce = 0;
+    static int warns_vbe = 0, warns_vbc = 0, warns_vce = 0, warns_vsub = 0;
 
     if (!ckt) {
         warns_vbe = 0;
         warns_vbc = 0;
         warns_vce = 0;
+        warns_vsub = 0;
         return OK;
     }
 
@@ -40,6 +41,8 @@ VBICsoaCheck(CKTcircuit *ckt, GENmodel *inModel)
                        ckt->CKTrhsOld [here->VBICcollNode]);
             vce = fabs(ckt->CKTrhsOld [here->VBICcollNode] -
                        ckt->CKTrhsOld [here->VBICemitNode]);
+            vsub = fabs(ckt->CKTrhsOld [here->VBICcollNode] -
+                       ckt->CKTrhsOld [here->VBICsubsNode]);
 
             if (vbe > model->VBICvbeMax)
                 if (warns_vbe < maxwarns) {
@@ -65,6 +68,13 @@ VBICsoaCheck(CKTcircuit *ckt, GENmodel *inModel)
                     warns_vce++;
                 }
 
+            if (vsub > model->VBICvsubMax)
+                if (warns_vsub < maxwarns) {
+                    soa_printf(ckt, (GENinstance*) here,
+                               "|Vce|=%g has exceeded Vce_max=%g\n",
+                               vsub, model->VBICvsubMax);
+                    warns_vsub++;
+                }
         }
     }