Disabling standby converter with phase-shifted full-bridge converter in server power supplies

This paper proposes to disable standby converter for improving the efficiency of a server computer power supply. By disabling the standby flyback converter after DC/DC stage is turned on, losses in standby flyback converter are removed in normal mode. When it is disabled, all outputs of the standby flyback converter are provided by phase-shifted full-bridge (PSFB) converter, so that the PSFB converter operates by itself. Since PSFB converter has much higher efficiency than the standby flyback converter, the system efficiency can be improved in the entire load condition. The feasibility of the proposed structure has been verified with 90-265V rms , 400V link voltage, 12V/62.5A main output, and 12V/2.1A standby output server power system.