Developing a high current 48V DC power supply: Design approaches based on SCALDO

According to data published by Electric Power Research Institute (EPRI), USA, energy consumption of cloud computing centres keep growing at 10% per annum, to reach over 200 billion kWh by year 2020. If the efficiency of a server power supply could be enhanced by even 1 %, an astronomical amount of energy could be saved every year. Supercapacitor assisted low drop-out regulator (SCALDO), is a high efficiency linear DC-DC converter technique suitable for high current DC-supplies. SCALDO can be extended to any load current, has DC-UPS capability, and does not require RFI/EMI filtering. Given the advantages of a linear DC-DC converter based on SCALDO, this paper presents the design approaches used in developing an off-the-line DC power supply of 48 V DC output. In order to maintain the necessary electrical isolation, and to use the advantages of the connected load seeing the high quality low-noise output of a linear regulator, a supercapacitor is used in series with a transformer which can toggle between fly-back to forward mode in transferring energy. Early result indicating the potential of this new extended-SCALDO technique is presented in the paper.