Characterization Of Self-driven Cascode-configuration Synchronous Rectifiers

As an effective way to improve the system efficiency of the converter,the synchronous rectifier is widely used in many applications.The self-driven synchronous rectifier is one of the development trends of the synchronous rectifier,due to its simplification and convenience.To make up the performance deficiencies of the single device,the compound switch technology is used in the self-driven synchronous rectifier.That is,aiming at the application requirements,a self-driven Cascode-configuration synchronous rectifier is proposed in this paper,which works as the active diode.In this paper,the development history of the power semiconductor device,soft-switching technology and synchronous rectifier is introduced firstly.Combining the application of the Cascode-configuration based compound switch technology in the Ga N device,the research purpose of this paper is pointed out.Secondly,based on the compound switch technology,this paper proposes a self-driven Cascode-configuration synchronous rectifier.Then,the static characteristics,switching process and dynamic characteristics of the proposed synchronous rectifier are analyzed in detail.The analytical expressions of the static parameters,voltage and current in the switching process are derived.According to the above analysis,it can be noted that the mismatch of the device parameter will cause the instability of the proposed synchronous rectifier.To ensure the stability of the proposed synchronous rectifier,the mechanism and solution of the parameter mismatch are further analyzed in this paper.Based on the analysis,the principle and optimization design method of the device parameters are given,ensuring the stability and dynamic performance of the proposed synchronous rectifier.Finally,a double-pulse test platform is built to verify the dynamic and static characteristics,switching mode and the optimized device parameters design method of the proposed synchronous rectifier.To verify the self-drive and synchronous rectification,the proposed synchronous rectifier is used in a 100 k Hz/ 1.4 k W LLC resonant converter.By using packaging technology,the rectifier loss can be further reduced.