In the twenty-first century, rapid advances are being made in the electric propulsion of vehicles as a countermeasure of global warming. In addition, CO2 emissions from all vehicles are to be stringently regulated to 95g/km by 2020. Thus, most automakers around the world have had to develop not only hybrid electric vehicles but also conventional internal combustion engine with energy-saving technology. Battery technology (Li-ion) and semiconductor technology (SiC, GaN) for automotive power supply systems have proceeded to the mass-production stage. In 2011VDA (German OEMs and suppliers) announced the adoption of DC48V for the market of 2020. In this paper, we analyze the needs and impact of DC48V and compare it with DC42V (current technology). We also try to portray the future view under DC60V for automotive power supply systems.