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netlist: document trapezoidal capacitor integration. (nw)

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couriersud 2020-04-23 23:03:58 +02:00
parent ecefb48992
commit 455b8fce2d
1 changed files with 47 additions and 1 deletions
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48
src/lib/netlist/analog/nld_generic_models.h
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@ -126,7 +126,9 @@ namespace analog
nl_fptype m_gmin;
};
#if 1
// Constant model for constant capacitor model
// Backward Euler
// "Circuit simulation", page 274
struct generic_capacitor_const
{
@ -148,8 +150,52 @@ namespace analog
private:
nl_fptype m_gmin;
};
#else
// Constant model for constant capacitor model
// Trapezoidal
// "Circuit simulation", page 278
struct generic_capacitor_const
{
public:
generic_capacitor_const(device_t &dev, const pstring &name)
: m_gmin(nlconst::zero())
, m_vn(0)
, m_in(0)
, m_trn(0.0)
{
plib::unused_var(dev, name);
}
// Returns { G, Ieq }
std::pair<nl_fptype, nl_fptype> timestep(nl_fptype cap, nl_fptype v, nl_fptype step) noexcept
{
const nl_fptype h(plib::reciprocal(step));
if (m_trn == 0.0)
{
const nl_fptype G(cap * h + m_gmin);
m_vn = v;
m_trn = h;
return { G, - G * v };
}
if (step < 1e-9)
printf("Help %e\n", step);
const nl_fptype Gn = nlconst::two() * cap * m_trn;
const nl_fptype inp1 = Gn * v - (m_in + Gn * m_vn);
const nl_fptype G(nlconst::two() * cap * h);
const nl_fptype Ieq(inp1 + G * v);
m_in = inp1;
m_vn = v;
m_trn = h;
return { G + m_gmin, -Ieq };
}
void setparams(nl_fptype gmin) noexcept { m_gmin = gmin; }
private:
nl_fptype m_gmin;
nl_fptype m_vn;
nl_fptype m_in;
nl_fptype m_trn;
};
#endif
// -----------------------------------------------------------------------------
// A generic diode model to be used in other devices (Diode, BJT ...)
// -----------------------------------------------------------------------------