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/***************************************************************************
* Copyright (C) 2003-2005 by David Saxton *
* [email protected] *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
***************************************************************************/
#include "bjt.h"
#include "diode.h"
#include "elementset.h"
#include "matrix.h"
#include <cmath>
using namespace std;
//BEGIN class BJTSettings
BJTSettings::BJTSettings()
{
I_S = 1e-16;
N_F = 1.0;
N_R = 1.0;
B_F = 100.0;
B_R = 1.0;
}
//END class BJTSettings
//BEGIN class BJTState
BJTState::BJTState()
{
reset();
}
void BJTState::reset()
{
for ( unsigned i = 0; i < 3; ++i )
{
for ( unsigned j = 0; j < 3; ++j )
A[i][j] = 0.0;
I[i] = 0.0;
}
}
BJTState BJTState::operator-( const BJTState & s ) const
{
BJTState newState( *this );
for ( unsigned i = 0; i < 3; ++i )
{
for ( unsigned j = 0; j < 3; ++j )
newState.A[i][j] -= s.A[i][j];
newState.I[i] -= s.I[i];
}
return newState;
}
//END class BJTState
//BEGIN class BJT
BJT::BJT( const bool isNPN )
: NonLinear()
{
V_BE_prev = 0.0;
V_BC_prev = 0.0;
m_pol = isNPN ? 1 : -1;
m_numCNodes = 3;
}
BJT::~BJT()
{
}
void BJT::add_map()
{
if (!b_status) return;
if ( !p_cnode[0]->isGround )
{
p_A->setUse( p_cnode[0]->n(), p_cnode[0]->n(), Map::et_unstable, false );
}
if ( !p_cnode[1]->isGround )
{
p_A->setUse( p_cnode[1]->n(), p_cnode[1]->n(), Map::et_unstable, false );
}
if ( !p_cnode[2]->isGround )
{
p_A->setUse( p_cnode[2]->n(), p_cnode[2]->n(), Map::et_unstable, false );
}
if ( !p_cnode[0]->isGround && !p_cnode[2]->isGround )
{
p_A->setUse( p_cnode[0]->n(), p_cnode[2]->n(), Map::et_unstable, false );
p_A->setUse( p_cnode[2]->n(), p_cnode[0]->n(), Map::et_unstable, false );
}
if ( !p_cnode[1]->isGround && !p_cnode[2]->isGround )
{
p_A->setUse( p_cnode[2]->n(), p_cnode[1]->n(), Map::et_unstable, false );
p_A->setUse( p_cnode[1]->n(), p_cnode[2]->n(), Map::et_unstable, false );
}
}
void BJT::add_initial_dc()
{
V_BE_prev = 0.0;
V_BC_prev = 0.0;
m_os.reset();
update_dc();
}
void BJT::updateCurrents()
{
if (!b_status)
return;
double V_B = p_cnode[0]->v;
double V_C = p_cnode[1]->v;
double V_E = p_cnode[2]->v;
double V_BE = (V_B - V_E) * m_pol;
double V_BC = (V_B - V_C) * m_pol;
double I_BE, I_BC, I_T, g_BE, g_BC, g_IF, g_IR;
calcIg( V_BE, V_BC, & I_BE, & I_BC, & I_T, & g_BE, & g_BC, & g_IF, & g_IR );
m_cnodeI[1] = I_BC - I_T;
m_cnodeI[2] = I_BE + I_T;
m_cnodeI[0] = -(m_cnodeI[1] + m_cnodeI[2]);
}
void BJT::update_dc()
{
if (!b_status)
return;
calc_eq();
BJTState diff = m_ns - m_os;
for ( unsigned i = 0; i < 3; ++i )
{
for ( unsigned j = 0 ; j < 3; ++j )
A_g( i, j ) += diff.A[i][j];
b_i( i ) += diff.I[i];
}
m_os = m_ns;
}
void BJT::calc_eq()
{
double V_B = p_cnode[0]->v;
double V_C = p_cnode[1]->v;
double V_E = p_cnode[2]->v;
double V_BE = (V_B - V_E) * m_pol;
double V_BC = (V_B - V_C) * m_pol;
double I_S = m_bjtSettings.I_S;
double N_F = m_bjtSettings.N_F;
double N_R = m_bjtSettings.N_R;
// adjust voltage to help convergence
double V_BEcrit = diodeCriticalVoltage( I_S, N_F * V_T );
double V_BCcrit = diodeCriticalVoltage( I_S, N_R * V_T );
V_BE_prev = V_BE = diodeVoltage( V_BE, V_BE_prev, V_T * N_F, V_BEcrit );
V_BC_prev = V_BC = diodeVoltage( V_BC, V_BC_prev, V_T * N_R, V_BCcrit );
double I_BE, I_BC, I_T, g_BE, g_BC, g_IF, g_IR;
calcIg( V_BE, V_BC, & I_BE, & I_BC, & I_T, & g_BE, & g_BC, & g_IF, & g_IR );
double I_eq_B = I_BE - V_BE * g_BE;
double I_eq_C = I_BC - V_BC * g_BC;
double I_eq_E = I_T - V_BE * g_IF + V_BC * g_IR;
m_ns.A[0][0] = g_BC + g_BE;
m_ns.A[0][1] = -g_BC;
m_ns.A[0][2] = -g_BE;
m_ns.A[1][0] = -g_BC + (g_IF - g_IR);
m_ns.A[1][1] = g_IR + g_BC;
m_ns.A[1][2] = -g_IF;
m_ns.A[2][0] = -g_BE - (g_IF - g_IR);
m_ns.A[2][1] = -g_IR;
m_ns.A[2][2] = g_BE + g_IF;
m_ns.I[0] = (-I_eq_B - I_eq_C) * m_pol;
m_ns.I[1] = (+I_eq_C - I_eq_E) * m_pol;
m_ns.I[2] = (+I_eq_B + I_eq_E) * m_pol;
}
void BJT::calcIg( double V_BE, double V_BC, double * I_BE, double * I_BC, double * I_T, double * g_BE, double * g_BC, double * g_IF, double * g_IR )
{
double I_S = m_bjtSettings.I_S;
double N_F = m_bjtSettings.N_F;
double N_R = m_bjtSettings.N_R;
double B_F = m_bjtSettings.B_F;
double B_R = m_bjtSettings.B_R;
// base-emitter diodes
double g_tiny = (V_BE < (-10 * V_T * N_F)) ? I_S : 0;
double I_F;
diodeJunction( V_BE, I_S, V_T * N_F, & I_F, g_IF );
double I_BEI = I_F / B_F;
double g_BEI = *g_IF / B_F;
double I_BEN = g_tiny * V_BE;
double g_BEN = g_tiny;
*I_BE = I_BEI + I_BEN;
*g_BE = g_BEI + g_BEN;
// base-collector diodes
g_tiny = (V_BC < (-10 * V_T * N_R)) ? I_S : 0;
double I_R;
diodeJunction( V_BC, I_S, V_T * N_R, & I_R, g_IR );
double I_BCI = I_R / B_R;
double g_BCI = *g_IR / B_R;
double I_BCN = g_tiny * V_BC;
double g_BCN = g_tiny;
*I_BC = I_BCI + I_BCN;
*g_BC = g_BCI + g_BCN;
*I_T = I_F - I_R;
}
void BJT::setBJTSettings( const BJTSettings & settings )
{
m_bjtSettings = settings;
if (p_eSet)
p_eSet->setCacheInvalidated();
}
//END class BJT
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