Implementation of DC-to-DC Isolated Converter by Using dpa425r for EV Drive

Abstract

Electric vehicle (EV) auxiliary systems require compact and efficient isolated DC–DC converters to power low-voltage electronics from intermediate DC buses. This paper presents the implementation of a 30 W isolated forward DC–DC converter using the DPA425R integrated switcher IC for EV auxiliary applications. The converter operates over a 36–75 V DC input range and provides a regulated 5 V isolated output suitable for battery management systems, sensors, and communication modules. The proposed design utilizes the integrated MOSFET, pulse-width modulation control, soft-start operation, thermal shutdown, undervoltage protection, and auto-restart features of the DPA425R to improve reliability under EV operating conditions. Mathematical modelling is incorporated for transformer and output-stage design. Simulation and experimental validation demonstrate output voltage regulation within ±2%, output ripple below 50 mV, and peak efficiency of approximately 88%. Comparative analysis with conventional flyback converters shows improved efficiency, reduced ripple, and better thermal performance. The proposed converter therefore provides a compact and reliable auxiliary power solution for EV applications.