Question

A buck converter has an input voltage V in = 24 V, switching frequency f s = 100 kHz, duty ratio d = 50%, load resistance R L = 10 Ω , inductance 100 μH, and capacitance 680 μF.

1) Calculate the following values, and include units in your answers :

a) Average output voltage, V_o

b) Average output current, I_o

c) Peak - to - peak current ripple, Δi_L

d) Output current that will cause the converter to enter DCM ( I 0,crit )

e) Load resistance that will cause the converter to enter DCM ( R crit )

f) Average voltage across the inductor in steady - state

g) Average current through the inductor in steady - state

h) Peak - to - peak voltage ripple across the capacitor, Δv_C

i) Average voltage across the capacitor in steady - state

j) Average current into the capacitor in steady - state

k) Approximate magnitude of the peak - to - peak ripple in the capacitor current, Δi_C

2) Sketch the following waveforms , and include the theoretical maximum and minimum values of each waveform:

a) q(t)

b) v_DS

c) v_diode

d) v_L

e) i_L

f) i_C

g) Output voltage (including ripple)

Answer 1