Project 1

1) Buck CCM,

Vin= 40V to 50V, fs= 100kHz

Vout = 30V, Pout = 500W,

So, Iout = P/V = 16.6A, Rout = 1.8ohm

D = Vo/Vin

D1 = 30V/40V = 0.75

D2 = 30V/50V = 0.6

V/L = di/dt, consider 10% inductor ripple, i.e 1.67A

(50 - 30) * 0.6 / (1.67 * 100 * 10^3) = 71.8 uH

Lmin = Io * (1-D) / 2fs = 3.75uH

Cout = Iout * (1-D) / fs*0.3 , dv = 0.3V

= 16.6 * 0.4 / 100K*0.3 = 221uF

Buck in CCM

Inductor choosen for CCM operation

Inductor Voltage current

2) To Operate the Same Topology in DCM mode,

I'm replacing the inductor value to 20uH (lesser the Lmin 3.3uH, as calculated above)

3) Boost

Vin = 20V - 30V, Vout = 40V , Pout = 600W, D = 0.5

Iout = 600/40 = 15A, R = 600/225 = 2.6ohm

Lmin = V * (1-D) / f * di

= (40 - 20) * 0.5 / 100K * 30A

= 3.34uH

I = C dv/dt

C = 15*0.5/ 0.4*100K = 187.5uF

Inductor Current

In DCM

Inductor Current