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netlist: document linearized diode model above max. dissip. [Couriersud]

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Document linearized diode model in the range exceeding maximum
dissipation. The intention is to have a faster convergence but this yet
not really is observable.
This commit is contained in:
couriersud 2020-03-21 15:30:53 +01:00
parent 735cffaa98
commit 8a87993201
1 changed files with 55 additions and 5 deletions
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60
src/lib/netlist/analog/nld_generic_models.h
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@ -11,6 +11,14 @@
#include "netlist/nl_base.h" #include "netlist/nl_base.h"
#include "netlist/nl_setup.h" #include "netlist/nl_setup.h"
//
// Set to 0 to use a linearized diode model in the range exceeding
// maximum dissipation. The intention is to have a faster
// convergence but this yet not really is observable
//
#define USE_TEXTBOOK_DIODE (1)
namespace netlist namespace netlist
{ {
namespace analog namespace analog
@ -147,8 +155,9 @@ namespace analog
, nlconst::magic(1) , nlconst::magic(1)
, nlconst::magic(1e-15) , nlconst::magic(1e-15)
, nlconst::magic(300.0)); , nlconst::magic(300.0));
m_name = name;
} }
pstring m_name;
// Basic math // Basic math
// //
// I(V) = f(V) // I(V) = f(V)
@ -162,7 +171,7 @@ namespace analog
{ {
if (TYPE == diode_e::BIPOLAR) if (TYPE == diode_e::BIPOLAR)
{ {
//printf("%s: %g %g\n", m_name.c_str(), nVd, (nl_fptype) m_Vd); #if USE_TEXTBOOK_DIODE
if (nVd > m_Vcrit) if (nVd > m_Vcrit)
{ {
// if the old voltage is less than zero and new is above // if the old voltage is less than zero and new is above
@ -187,6 +196,28 @@ namespace analog
m_Id = IseVDVt - m_Is; m_Id = IseVDVt - m_Is;
m_G = IseVDVt * m_VtInv + m_gmin; m_G = IseVDVt * m_VtInv + m_gmin;
} }
#else
//printf("%s: %g %g\n", m_name.c_str(), nVd, (nl_fptype) m_Vd);
m_Vd = nVd;
if (nVd > m_Vcrit)
{
m_Id = m_Icrit_p_Is - m_Is + (m_Vd - m_Vcrit) * m_Icrit_p_Is * m_VtInv;
m_G = m_Icrit_p_Is * m_VtInv + m_gmin;
}
else if (m_Vd < m_Vmin)
{
m_G = m_gmin;
//m_Id = m_Imin + (m_Vd - m_Vmin) * m_gmin;
//m_Imin = m_gmin * m_Vt - m_Is;
m_Id = (m_Vd - m_Vmin + m_Vt) * m_gmin - m_Is;
}
else
{
const auto IseVDVt = plib::exp(m_logIs + m_Vd * m_VtInv);
m_Id = IseVDVt - m_Is;
m_G = IseVDVt * m_VtInv + m_gmin;
}
#endif
} }
else if (TYPE == diode_e::MOS) else if (TYPE == diode_e::MOS)
{ {
@ -212,14 +243,29 @@ namespace analog
m_gmin = gmin; m_gmin = gmin;
m_Vt = n * temp * nlconst::k_b() / nlconst::Q_e(); m_Vt = n * temp * nlconst::k_b() / nlconst::Q_e();
m_VtInv = plib::reciprocal(m_Vt);
#if USE_TEXTBOOK_DIODE
m_Vmin = nlconst::magic(-5.0) * m_Vt; m_Vmin = nlconst::magic(-5.0) * m_Vt;
// Vcrit : f(V) has smallest radius of curvature rho(V) == min(rho(v)) // Vcrit : f(V) has smallest radius of curvature rho(V) == min(rho(v))
m_Vcrit = m_Vt * plib::log(m_Vt / m_Is / nlconst::sqrt2()); m_Vcrit = m_Vt * plib::log(m_Vt / m_Is / nlconst::sqrt2());
m_VtInv = plib::reciprocal(m_Vt); #else
} m_Vmin = plib::log(m_gmin * m_Vt / m_Is) * m_Vt;
//m_Imin = plib::exp(m_logIs + m_Vmin * m_VtInv) - m_Is;
//m_Imin = m_gmin * m_Vt - m_Is;
// Fixme: calculate max dissipation voltage - use use 0.5 (500mW) here for typical diode
// P = V * I = V * (Is*exp(V/Vt) - Is)
// P ~= V * I = V * Is*exp(V/Vt)
// ln(P/Is) = ln(V)+V/Vt ~= V - 1 + V/vt
// V = (1+ln(P/Is))/(1 + 1/Vt)
m_Vcrit = (1.0 + plib::log(0.5 / m_Is)) / (1.0 + m_VtInv);
//printf("Vcrit: %f\n", m_Vcrit);
m_Icrit_p_Is = plib::exp(m_logIs + m_Vcrit * m_VtInv);
//m_Icrit = plib::exp(m_logIs + m_Vcrit * m_VtInv) - m_Is;
#endif
}
nl_fptype I() const noexcept { return m_Id; } nl_fptype I() const noexcept { return m_Id; }
nl_fptype G() const noexcept { return m_G; } nl_fptype G() const noexcept { return m_G; }
@ -241,6 +287,10 @@ namespace analog
nl_fptype m_VtInv; nl_fptype m_VtInv;
nl_fptype m_Vcrit; nl_fptype m_Vcrit;
#if !USE_TEXTBOOK_DIODE
//nl_fptype m_Imin;
nl_fptype m_Icrit_p_Is;
#endif
}; };