Recently, Associate Professor Zhan Chenchang’s research group at the Shenzhen-Hong Kong College of Microelectronics, Southern University of Science and Technology (SUSTech), has made a notable advancement in DC-DC switching power supply chip technology. Doctoral candidate Zhang Nian from the team introduced an innovative Fly-buck (flying buck) type DC-DC converter, distinguished by its high efficiency under light-load conditions and an implicit isolated-side feedback mechanism. The findings, detailed in the paper “A Light-Load Optimized 7–100-V Dual-Output Fly-Buck Converter With an Implicit Feedback of the Isolated Output in DCM,” were published in the IEEE Journal of Solid-State Circuits (JSSC), a premier journal in integrated circuit design.

The Fly-buck converter stands out for its ability to deliver one non-isolated output and multiple isolated outputs at a reduced cost, making it highly suitable for applications such as industrial power supplies and BMS protection boards for two-wheeled electric vehicles. To tackle the challenge of low efficiency in traditional designs under light-load scenarios, the research team developed a groundbreaking discontinuous conduction mode that minimizes zero-current time. By integrating this mode with an enhanced on-time generator that incorporates an implicit feedback mechanism for the isolated-side output, the converter substantially lowers the switching frequency under light-load conditions. This not only enhances energy efficiency but also maintains the isolated-side load capacity.

Measurements indicate that with a 48V input, the converter achieves up to a 24% improvement in light-load efficiency compared to conventional methods. Moreover, when the isolated-side load current remains below 150mA, the output voltage drop is kept within 10%. This research was a collaborative effort between the Shenzhen-Hong Kong College of Microelectronics at SUSTech and Moregain (Shenzhen) Technology Co., Ltd., and was supported by funding from the National Natural Science Foundation of China, the Shenzhen Science and Technology Innovation Commission, and horizontal research projects from associated enterprises.