Efficiency Evaluation of a Modular Step-Down 48-to-1V Converter with Shared Load Current

This paper presents the results of the efficiency analysis of a modular DC-DC converter with an input voltage of 48 V and an output voltage of 1 V. This is a single stage Voltage Regulator Module (VRM), characterized by a high output current, but its modular structure allows reducing resistive losses. The output current is divided into parallel chokes and semiconductor cells, hence the expected decrease in its square value. The converter uses an input capacitor divider to reduce voltage stress across some components. The article presents the concept of system topology and control verified by the demonstration of current and voltage waveforms. The analysis of the efficiency of the system demonstrates the main sources of losses in the system and its efficiency, which is very important for the correct design of the converter. The results are presented for a case of a MOSFET-based four-module converter with a rated maximum power of 350 W and an output voltage of 1V.