Cider simulator support file.

src/spicelib/devices/limit.c

@@ -0,0 +1,322 @@
+/**********
+Copyright 1991 Regents of the University of California.  All rights reserved.
+Author:	1987 Kartikeya Mayaram, U. C. Berkeley CAD Group
+**********/
+
+/* limiting routines for junction voltages */
+
+double DvRevMax = 0.5, DvFwdMax = 50.0e-3;
+
+double 
+limitResistorVoltage( double vnew, double vold, int *icheck )
+{
+    double vlim, vinc;
+
+    if( vnew > vold ) {
+	vinc = 0.5;
+	vlim = vold + vinc;
+	if( vnew < vlim ) {
+	    *icheck = 0;
+	    return( vnew );
+	} else {
+	    *icheck = 1;
+	    return( vlim );
+	}
+    } else if ( vnew < vold ) {
+	vinc = 0.5;
+	vlim = vold - vinc;
+	if( vnew > vlim ) {
+	    *icheck = 0;
+	    return( vnew );
+	} else {
+	    *icheck = 1;
+	    return( vlim );
+	}
+    } else { /* vnew == vold */
+	*icheck = 0;
+	return( vnew );
+    }
+    /* NOTREACHED */
+}
+
+double limitJunctionVoltage( double vnew, double vold, int *icheck )
+{
+    double vlim, vinc;
+
+    if( vold >= 0.0 ) {
+	if( vnew > vold ) {
+	    if( vold > 0.65 ) 
+		vinc = DvFwdMax;
+	    else 
+		vinc = 2.0 * DvFwdMax;
+	    vlim = vold + vinc;
+	    if( vnew < vlim ) {
+		*icheck = 0;
+		return( vnew );
+	    }
+	    else {
+		*icheck = 1;
+		return( vlim );
+	    }
+	}
+	else if ( vnew == vold )  {
+	    *icheck = 0;
+	    return ( vnew );
+	}
+	else {
+	    /* vnew is less than vold */
+	    /* case 1: vnew is positive */
+	    /* case 2: vnew is negative, ensure it goes thru zero */
+	    if( vnew < 0.0 && vold <= 0.05 && vold > 0.0) {
+		/* limit to zero when vnew < 0.0 and vold |= 0.0 */
+		*icheck = 1;
+		return( 0.0 );
+	    }
+	    vinc = 2.0 * DvFwdMax;
+	    vlim = vold - vinc;
+	    if( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    }
+	    else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	}
+    }
+    else {
+	if( vnew < vold ) {
+	    vlim = vold - DvRevMax;
+	    if ( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    }
+	    else
+	    {
+		*icheck = 0;
+		return( vnew );
+	    }
+	}
+	else {
+	    /* vnew > vold. check if vnew less than 0.0 */
+	    if( vnew < 0.0 ) {
+		vlim = vold + 1.0;
+		if( vnew < vlim ) {
+		    *icheck = 0;
+		    return( vnew );
+		}
+		else {
+		    *icheck = 1;
+		    return( vlim );
+		}
+	    }
+	    else {
+		vlim = vold + 2.0 * DvRevMax;
+		*icheck = 1;
+		if( vlim > 0.0 )
+		    return( 0.0 );
+		else
+		    return( vlim );
+	    }
+	}
+    }
+}
+	    
+	    
+double limitVbe( double vnew, double vold, int *icheck )
+{
+    double vlim, vinc;
+    if( vold >= 0.0 ) {
+	if( vnew > vold ) {
+	    if( vold > 0.9 ) 
+		/* deep high-level injection conditions */
+		vinc = 0.01;
+	    else if( vold > 0.85 ) 
+		vinc = 0.025;
+	    else if( vold > 0.65 ) 
+		vinc = 0.05;
+	    else 
+		vinc = 0.10;
+	    vlim = vold + vinc;
+	    if( vnew < vlim ) {
+		*icheck = 0;
+		return( vnew );
+	    }
+	    else {
+		*icheck = 1;
+		return( vlim );
+	    }
+	}
+	else if ( vnew == vold )  {
+	    *icheck = 0;
+	    return ( vnew );
+	}
+	else {
+	    /* vnew is less than vold */
+	    /* case 1: vnew is positive */
+	    /* case 2: vnew is negative, ensure it goes thru zero */
+	    if( vnew < 0.0 && vold <= 0.05 && vold > 0.0) {
+		/* limit to zero when vnew < 0.0 and vold |= 0.0 */
+		*icheck = 1;
+		return( 0.0 );
+	    }
+	    vinc = 0.1;
+	    vlim = vold - vinc;
+	    if( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    }
+	    else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	}
+    }
+    else {
+	if( vnew < vold ) {
+	    vlim = vold - 0.1;  /* XXX Originally 0.1 */
+	    if ( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    }
+	    else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	}
+	else {
+	    /* vnew > vold. check if vnew less than 0.0 */
+	    if( vnew < 0.0 ) {
+		vlim = vold + 1.0;
+		if( vnew < vlim ) {
+		    *icheck = 0;
+		    return( vnew );
+		}
+		else {
+		    *icheck = 1;
+		    return( vlim );
+		}
+	    }
+	    else {
+		vlim = vold + 1.0;
+		*icheck = 1;
+		if( vlim > 0.0 )
+		    return( 0.0 );
+		else
+		    return( vlim );
+	    }
+	}
+    }
+}
+
+double limitVce( double vnew, double vold, int *icheck )
+{
+    double vlim;
+    if( vold >= 0.0 ) {
+	if( vnew > vold ) {
+	    vlim = vold + 1.0;
+	    if( vnew < vlim ) {
+		*icheck = 0;
+		return( vnew );
+	    } else {
+		*icheck = 1;
+		return( vlim );
+	    }
+	} else {
+	    vlim = vold - 0.5; /* XXX Originally 0.2 */
+	    if( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    } else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	}
+    } else {
+	if( vnew < vold ) {
+	    vlim = vold - 1.0;
+	    if ( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    } else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	} else {
+	    /* vnew > vold. check if vnew less than 0.0 */
+	    if( vnew < 0.0 ) {
+		vlim = vold + 1.0;
+		if( vnew < vlim ) {
+		    *icheck = 0;
+		    return( vnew );
+		} else {
+		    *icheck = 1;
+		    return( vlim );
+		}
+	    } else {
+		vlim = vold + 1.0;
+		*icheck = 1;
+		if( vlim > 0.0 )
+		    return( 0.0 );
+		else
+		    return( vlim );
+	    }
+	}
+    }
+}
+
+double limitVgb( double vnew, double vold, int *icheck )
+{
+    double vlim;
+    if( vold >= 0.0 ) {
+	if( vnew > vold ) {
+	    vlim = vold + 1.0;
+	    if( vnew < vlim ) {
+		*icheck = 0;
+		return( vnew );
+	    } else {
+		*icheck = 1;
+		return( vlim );
+	    }
+	} else {
+	    vlim = vold - 0.2;
+	    if( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    } else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	}
+    } else {
+	if( vnew < vold ) {
+	    vlim = vold - 1.0;
+	    if ( vlim > vnew ) {
+		*icheck = 1;
+		return( vlim );
+	    } else {
+		*icheck = 0;
+		return( vnew );
+	    }
+	} else {
+	    /* vnew > vold. check if vnew less than 0.0 */
+	    if( vnew < 0.0 ) {
+		vlim = vold + 1.0;
+		if( vnew < vlim ) {
+		    *icheck = 0;
+		    return( vnew );
+		} else {
+		    *icheck = 1;
+		    return( vlim );
+		}
+	    } else {
+		vlim = vold + 1.0;
+		*icheck = 1;
+		if( vlim > 0.0 )
+		    return( 0.0 );
+		else
+		    return( vlim );
+	    }
+	}
+    }
+}