DC-UPS Capability for the SCALDO-Assisted 48-V Google Rack Power Architecture

In order to reduce energy losses in high energy consuming data centers, Google introduced their 48-V rack power architecture in 2016 to replace the previous 12-V DC power distribution line. With the DC voltage increased by 4 times the ohmic losses can be reduced by 16 times. This new architecture is expected to be enhanced with rack-level DC-UPS.Compared to traditional very high-frequency switch mode DC-DC converters with their complexity and interference issues, a typical linear converter generates low-noise high-quality DC, albeit with the very low efficiency. The supercapacitor (SC) assisted low drop-out (SCALDO) regulator is a unique new DC-DC converter that resolves this low-efficiency issue. This paper provides a new design approach to achieve a low-frequency supercapacitor-based energy recovery technique for a 48-V DC power supply with efficiencies comparable to switch mode power supplies but with the added advantage of two-stage DC-UPS capability at no additional cost.