Question

The working principle of SMPS is based on

• A. Integral control principle
• B. Frequency control principle
• C. Chopper principle
• D. Phase control principle

Hint:

SMPS uses switching (chopper action) for efficient power conversion.

Answer 1

The Correct Option is C

Step 1: Describe the switching action of SMPS.
In a Switched Mode Power Supply, the main power transistor operates as a switch: either fully ON (near-zero voltage drop) or fully OFF (no current). This on-off switching at high frequency "chops" the DC supply into pulses, identical to a DC chopper circuit.

Step 2: Explain output voltage regulation via duty cycle.
The duty cycle $D = T_{ON}/(T_{ON}+T_{OFF})$ controls the average output voltage: $V_{out} = D \times V_{in}$ (for a buck converter). By varying $D$ through pulse-width modulation (PWM), the output voltage is regulated.

Step 3: Confirm the working principle.
This rapid ON-OFF switching -- identical to chopper operation -- allows small, lightweight magnetic components and high efficiency. \[ \boxed{\text{Chopper principle}} \]