Full-Wave Bridge Rectifier DC Power Supply

Objective

The goal of this project is to design a circuit that produces a 5V DC output at 2A, with a ripple voltage under 5% to ensure stable and high-quality power delivery.

Motivation

I wanted to explore power electronics by designing a power conversion circuit using a full-wave bridge rectifier, a widely used component widely used in power supplies, battery chargers, and many other devices. This project helped me understand its role in AC-to-DC conversion and how its output characteristics can be adapted using different components.

Technical overview

First, the AC voltage passes through a step-down transformer (turns ratio is 24.2 : 1), reducing the peak voltage from 170V to approximately 7.1V.

Next, the voltage enters the bridge rectifier, where one of the two forward-biased diodes conducts, depending on the direction of current flow. At the rectifier's output, a pulsating DC voltage is produced. The peak voltage drops to just above 5V due to the diodes' forward voltage drop.

This DC voltage then passes through a smoothing capacitor, which reduces ripple by charging when the voltage is high and discharging when the voltage is low, effectively filling in the gaps between the pulsating DC peaks and providing a more stable output. Finally, the voltage is delivered to the load resistor, which simulates a 2A current draw.

Design choices

I chose to design this power supply using a full-wave bridge rectifier instead of a half-wave rectifier because it utilizes both the positive and negative halves of the AC waveform, resulting in a higher average DC output voltage and significantly lower ripple voltage. This improves the efficiency of the power conversion and provides a cleaner, more stable power supply, which is important for the proper operation of electronic devices.