Gao Yuan Research Group of School of Microelectronics Has Made New Progress in Power Chip Design

2020-07-31 Research News views：12125

Recently, Gao Yuan, Assistant Professor of School of Microelectronics of Southern University of Science and Technology (SUSTech), a research team led by Mo Guotai, Professor of Hongkong University of Science and Technology, and Coileasy Electronic Technology Co., Ltd. have jointly proposed a hybrid LED driving power chip with improved efficiency and integration for AC mains input. Relevant results have been published in IEEE Journal of Solid-State Circuits (JSSC), a top journal in the field of integrated circuit design, with the title "A Hybrid LED Driver with Improved Efficiency".

LED lighting has already found its way into every household, but the design of high-performance LED driving power chips is still faced with challenges. It is difficult for traditional solutions to improve the power factor and ensure the system efficiency while raising the integration of the system. In order to solve the problem, a hybrid driving power supply scheme is proposed in this paper. This solution combines the advantages of traditional buck converters and non-inductive driving solutions, and realizes the monolithic integration of power switch tubes and control chips. Meanwhile, the current path and switching state can be automatically selected according to the changes of AC input voltage in order to ensure high efficiency within the whole range. In addition, according to different application scenarios, the system can be configured to work in two modes of high power factor and low flash frequency. The chip is taped out by a 0.35μm high-voltage CMOS process. The test results show that the hybrid scheme only uses 6.8 μH inductance under AC mains input, and can maintain normal work in different modes. Compared with the mainstream commercial products of AC input, the required inductance value is reduced by more than 10 times, which effectively reduces the size of the system and improves the system integration. The efficiency of the peak conversion of the system is over 95% and 92% respectively under high power factor and low flash frequency mode, with the power factor reaching 0.986 and 0.918 respectively.

Gao Yuan is the first author and SUSTech is the first unit of the paper. This is also the first time that SUSTech has published a paper on IEEE JSSC. IEEE JSSC is a top international journal in the field of integrated circuit design. It accepts the world's leading chip design results and requires that the proposed new technology must have actual chip verification.

Paper link：https://ieeexplore.ieee.org/abstract/document/9082093

Figure 1   Hybrid LED driving power chip with improved efficiency and integration (a) system structure; (b) chip photo; (c) test results under different working modes.

The main research direction of Gaoyuan Research Group of School of Microelectronics is the design of power supplies and analogue integrated circuits for 5G communication equipment, fast charging, LED lighting and automotive electronics. The research results of the research group have been published in many top journals and conferences in the field of integrated circuit design, including IEEE JSSC, IEEE ISSCC, IEEE TCAS-I and IEEE Symposium on VLSI.