SMPS Based 48V/8A Battery Charger (CV Mode) Constant Voltage

This paper presents the design and implementation of a switch- mode power supply (SMPS) based battery charger delivering 48 V at 8 A with precise constant- voltage regulation. The charger employs a high- frequency, pulse- width- modulated (PWM) buck converter topology optimized for efficiency and compactness. Key features include a digital control loop using a microcontroller- based PID algorithm to maintain output voltage within ±0.5% under varying load and input conditions, and a programmable soft- start sequence to limit inrush current during connection. Input power factor correction (PFC) ensures compliance with international grid- compatibility standards, while synchronous rectification in the output stage achieves efficiencies exceeding 94%. Protection mechanisms, overvoltage, overcurrent, and thermal shutdown are integrated to ensure safe operation and battery longevity. Experimental results on a laboratory prototype demonstrate stable 48 V output with rapid response to load transients and an overall efficiency of 92.5% at full load. The modular design allows scalability to higher power levels, making it suitable for modern energy storage systems in telecommunications, electric vehicles, and renewable- energy applications.