Scicos Block
fr - eng


Electrical diode

\epsfig{file=Diode.eps,width=90.00pt}

Contents

Description

This component consists of a simple diode parallel with an ohmic resistance ($ R$ ). The current passing through this component is defined as a function of the voltage across the ports, i.e.,

$\displaystyle i = I_{ds} ( \exp^{v/V_t}- 1)+\frac{v}{R}$

where $ I_{ds}$ and $ V_t$ are the saturation current and the voltage equivalent of temperature, respectively. If the exponent $ v/V_t$ reaches a certain limit ($ Maxexp$ ), the diode characterisic becomes linear to avoid overflow.

Dialog box

Set Diode block parameter  
Saturation cuurent (A) 0.000001
Voltage equivalent to temperature (Volt) 0.04
Max exponent for linear continuation 15
R (ohm) 1.000E+08

Default properties

Interfacing function

Diode.sci

Modelica model


class Diode "Simple diode" 
   Pin p, n;
    parameter Real Ids=1.e-6 "Saturation current";
    parameter Real Vt=0.04   "Voltage equivalent of temperature (kT/qn)";
    parameter Real Maxexp=15 "Max. exponent for linear continuation";
    parameter Real R=1.e8 "Parallel ohmic resistance";
    Real v;
  equation 
   v = p.v - n.v;

   p.i = if noEvent(v/Vt > Maxexp) then 
	Ids*(Modelica.Math.exp(Maxexp)*(1 + v/Vt - Maxexp) - 1) + v/R 
  else 
	Ids*(Modelica.Math.exp(v/Vt) - 1) + v/R;

   p.i = -n.i;

  end Diode;