Linear and Switched Mode Converters Basics

Introduction

Power converters are electronic systems designed to convert electrical power from one form to another. They are classified based on the type of input and output they handle:

1. DC-DC Converters: Convert Direct Current (DC) input to a regulated DC output
2. DC-AC Converters (Inverters): Convert DC input to Alternating Current (AC) output
3. AC-DC Converters (Rectifiers): Convert AC input to a regulated DC output
4. AC-AC Converters: Modify the frequency or voltage of an AC input to an AC output

Linear Converters

• Operate by dissipating excess voltage as heat through a pass element (Metal–Oxide–Semiconductor Feld-Effect Transistor (MOSFET) or transistor)
• Simple design but limited to step-down applications
• Efficiency depends on input-output voltage ratio: Efficiency = (Vout / Vin) x 100%

Switched-Mode Converters (Switchers)

• Use high-frequency switching to regulate output
• Efficiency is higher, especially for large voltage differentials
• Support multiple topologies:
  • Non-Isolated: Direct connection between input and output ground
    • Buck (Step-down): Reduces voltage
    • Boost (Step-up): Increases voltage
    • Buck-Boost: Combines buck and boost for step-up/step-down capability
  • Isolated: Uses a transformer for input-output isolation
    • Common in high-voltage applications, ensuring safety and galvanic isolation

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