Question

The duty cycle value of a buck converter when the switching frequency is 250 kHz and the ON time is 2\( \mu s \) is:

• A. 0.4
• B. 0.8
• C. 0.5
• D. 0.2

Hint:

The duty cycle of a buck converter is given by \( D = \frac{T_{\text{ON}}}{T_{\text{total}}} \). Increasing the duty cycle increases the output voltage.

Answer 1

The Correct Option is D

Step 1: The duty cycle (\( D \)) of a buck converter is given by: \[ D = \frac{T_{\text{ON}}}{T_{\text{total}}} \] where:
- \( T_{\text{ON}} = 2 \mu s \) (ON time of the switch), - \( T_{\text{total}} = \frac{1}{f_s} \) (Total switching period), - \( f_s = 250 \) kHz (Switching frequency). 
Step 2: Calculating the total switching period: \[ T_{\text{total}} = \frac{1}{250 \times 10^3} = 4 \mu s \] 
Step 3: Computing the duty cycle: \[ D = \frac{2 \mu s}{4 \mu s} = 0.2 \] 
Step 4: Thus, the correct answer is 0.2.