library ieee, ieee_proposed;
use ieee.electrical_systems.all;
use ieee.math_real.all;

entity CalcBuckParams is
  
  generic (
    Vin     : voltage := 42.0;         -- Input Voltage [Volts]
    Vout    : voltage := 4.8;          -- Output Voltage [Volts]
    Vd      : voltage := 0.7;          -- Diode Voltage [Volts]
    Imin    : current := 15.0e-3;      -- Min output current [Amps]
	Vripple : voltage := 100.0e-3;     -- Output Voltage Ripple [Volts]
	Resr    : resistance := 50.0e-3);

  port (
    quantity Fsw : in  real;           -- Switching Frequency [Hz]
    quantity Lmin : out inductance;    -- Minimum Inductance [Henries]
	quantity Cmin : out capacitance);  -- Minimum Capacitance [Farads]

end entity CalcBuckParams;

architecture ideal of CalcBuckParams is

constant D : real := (Vout + Vd)/(Vin + 1.0e-9);   -- Duty Cycle
quantity Ts : real;                     -- Period
quantity Ton : real;                    -- On Time

quantity Fxo, Fp1, Fp2, Fz : real; 

begin  -- architecture behavioral

Ts == 1.0/(Fsw+1.0e-9);
Ton == D*Ts;
Lmin == (Vin - Vout) * Ton/(2.0*Imin);
Cmin == (2.0*Imin)/(8.0*Fsw*Vripple+1.0e-9);

-- Calculate compensator parameters
Fxo == Fsw/5.0;  -- desired crossover frequency
Fp1 == Fxo * 1.5;
Fp2 == 1.0/(math_2_pi*Resr*Cmin*4.0+1.0e-9);
Fz == 1.0/(math_2_pi*sqrt(Lmin*Cmin*4.0)+1.0e-9);

end architecture ideal;