electronics/simulation/nonlinear.h

0001 /***************************************************************************
0002  *   Copyright (C) 2003-2005 by David Saxton                               *
0003  *   david@bluehaze.org                                                    *
0004  *                                                                         *
0005  *   This program is free software; you can redistribute it and/or modify  *
0006  *   it under the terms of the GNU General Public License as published by  *
0007  *   the Free Software Foundation; either version 2 of the License, or     *
0008  *   (at your option) any later version.                                   *
0009  ***************************************************************************/
0010
0011 #ifndef NONLINEAR_H
0012 #define NONLINEAR_H
0013
0014 #include "element.h"
0015
0016 /**
0017 @short Represents a non-linear circuit element (such as a diode)
0018 @author David Saxton
0019 */
0020 class NonLinear : public Element
0021 {
0022 public:
0023     NonLinear();
0024
0025     bool isNonLinear() const override
0026     {
0027         return true;
0028     }
0029     /**
0030      * Newton-Raphson iteration: Update equation system.
0031      */
0032     virtual void update_dc() = 0;
0033
0034 protected:
0035     /**
0036      * The diode current.
0037      */
0038     double diodeCurrent(double v, double I_S, double N) const;
0039     /**
0040      * Conductance of the diode - the derivative of Schockley's
0041      * approximation.
0042      */
0043     double diodeConductance(double v, double I_S, double N) const;
0044     /**
0045      * Limits the diode voltage to prevent divergence in the nonlinear
0046      * iterations.
0047      */
0048     double diodeVoltage(double v, double V_prev, double N, double V_lim) const;
0049     /**
0050      * Current and conductance for a diode junction.
0051      */
0052     void diodeJunction(double v, double I_S, double N, double *I, double *g) const;
0053     /**
0054      * Current and conductance for a MOS diode junction.
0055      */
0056     void mosDiodeJunction(double V, double I_S, double N, double *I, double *g) const;
0057     /**
0058      * Limits the drain-source voltage to prevent divergence in the
0059      * nonlinear iterations.
0060      */
0061     double fetVoltageDS(double V, double V_prev) const;
0062     /**
0063      * Limits the forward voltage to prevent divergence in the nonlinear
0064      * iterations.
0065      */
0066     double fetVoltage(double V, double V_prev, double Vth) const;
0067
0068     double diodeLimitedVoltage(double I_S, double N) const;
0069 };
0070
0071 #endif