100Vdc to 5Vdc 3 Amps Convertor ( Transistors Base)

100 VDC to 5 VDC (3A) Transistor-Based Step-Down Converter

Project Overview

This is a reliable, transistor-based linear step-down DC-DC converter designed to step down a high-voltage direct current input of 100 VDC to a stable 5 VDC output capable of delivering up to 3 Amps of current.

Key Specifications

• Input Voltage: 100 VDC

• Intermediate Voltage: ~15 VDC (pre-regulated stage)

• Output Voltage: 5 VDC

• Max Output Current: 3 A

• 
  

  
  

• Key Components & Working Principle

  1. • 1. Power Transistors (MJE13007 / MJE13009):

       These high-voltage NPN transistors act as the main series-pass power elements.

  2. Zener Diode Stage:

     • Zener diodes are utilized to establish a stable reference voltage and help stabilize the intermediate voltage stage (bringing the high input voltage down closer to a manageable ~15 VDC).

  3. Voltage Regulator IC (7805):

     • The intermediate ~15 VDC output from the transistor/Zener stage is fed into a standard 7805 linear regulator IC, which cleanly steps it down to the final, stable 5 VDC output required for your load.

  Circuit Advantages

  • High-Voltage Handling: Efficiently bridges a wide voltage gap safely using robust high-voltage transistors.

  • Stable Output: The two-stage reduction (transistor/Zener pre-regulator followed by the 7805 IC) ensures a clean and steady 5V output.

  • Reliability: Built with heavy-duty components designed to handle high thermal loads when properly paired with heatsinks.  

• 
  

•