Current Sharing Control and Influencing Factors for Parallel GaN FETs

GaN (Gallium nitride) FET is widely used in power electronics due to its excellent performance. However, the limited power capacity of individual GaN FET hinders their use in high-power applications. To address this issue, parallel connection of multiple GaN FETs is considered to be an effective solution. Nevertheless, disparities in parameters of paralleled GaN FET devices and asymmetry in peripheral circuit parameters lead to current imbalance among the devices. In this paper, a multi-period adjustment of drive voltage variability and signal compensation active current sharing method is proposed. Firstly, by establishing the current sharing test circuit and conducting a comprehensive analysis of device and circuit parameters, both static and dynamic current imbalances among paralleled devices and their influencing factors are analyzed. Then, based on the master-slave control topology, a multi-cycle iterative control combining drive signal delay and current slope control is proposed to improve the dynamic current balance between parallel branches. Finally, through simulation, the effectiveness of proposed method in the application of GaN FETs parallel current sharing is verified.