Skip to content

Buck Converter Example

Overview

The buck converter is the fundamental step-down DC-DC topology. This example demonstrates basic operation with open-loop PWM control.

Difficulty: Beginner

Estimated Time: 15-20 minutes

Learning Objectives

  • Understand buck converter operation
  • Observe CCM waveforms
  • Verify Vout = D × Vin relationship

Circuit Description

    +Vin ──┬──[S]──┬──[L]──┬── +Vout
           │       │       │
           │      [D]     [C]     [R]
           │       │       │       │
    GND ───┴───────┴───────┴───────┴── GND

Parameters

Parameter Value Unit
Vin 48 V
Vout 12 V
D (duty cycle) 0.25 -
fs 100 kHz
L 100 μH
C 100 μF
R (load) 4.8 Ω

Expected Results

Signal Value
Vout (avg) 12 V
IL (avg) 2.5 A
ΔIL 0.9 A p-p
ΔVout 22 mV p-p

Exercises

  1. Vary D from 0.1 to 0.5, verify Vout = D × Vin
  2. Change load to light (48Ω), observe DCM
  3. Reduce L to 10μH, observe increased ripple