Implementing High Efficiency Using Dual-Switch Quasi-Resonant (QR) Flyback for All-In-One PC Power Supply

摘要

In general, a Quasi-Resonant (QR) Flyback Converter which can be designed easily shows lower turn-on loss compared to conventional hard switching.LLC converter can achieve very good efficiency, but it is not easy to design. And dual switch QR Flyback can achieve good efficiency which is higher than single switch, but close to LLC. This is as a result of the callback function of reset energy for transformer and by using lower Vds MOSFET such as 500V with lower Rds_on, if PFC operates as 2 levels output according to high/low line, MOSFET can turn on at almost zero voltage at low line to improve efficiency much more to get higher efficiency at low line. This paper presents the operation principle of dual-switch Quasi-Resonant converter based on 2 levels PFC bus voltage. The design procedure is also outlined. And an example which can be used for All-In-One PC power shows the design is favorable compared to the other two structures, which validate its superiority on AIO power supply.