Research On Common Mode Transient Immunity Of GaN Semiconductor Power Device Driver

With low on-resistance,parasitic capacitance and no reverse recovery process,enhanced GaN devices support higher switching frequency and higher power density compared with Si-based power devices,and have significant advantages in 5G communication,PD fast charging and other fields,and have been widely used in recent years.For GaN gate drivers in high frequency applications,due to the fast switching speed of GaN devices,the switching node voltage d V/dt of the driver can reach more than 200 V/ns.The high d V/dt of switching node voltage is easy to cause the misopening of power tube.Therefore,it is of great significance to study the CMTI of GaN actuator.In this paper,by analyzing the structure of the enhanced GaN device,the switching process and the influence of CMT noise on the half-bridge gate driver,the factors that affect the CMTI capability of the chip are obtained,and a magnetically coupled digital isolated gate driver based on the on-chip transformer is designed.Based on the differential structure of the transformer on the chip,the geometric parameters of the transformer on the chip are optimized by Ansys HFSS.The CMTI capability of the transmitter can be improved without increasing the power consumption by adopting the circuit of the transmitter which can adjust the tail current dynamically.The rectifier circuit based on Gilbert mixer architecture can be realized by RC low-pass filtering network.Because the circuit structure is highly symmetrical,it has a strong ability to suppress CMT noise.In this paper,the design and simulation of GaN digital isolated gate driver based on on-chip transformer are completed based on 0.18 μm process.The CMTI capacity of the chip is higher than 200 V/ns,and the typical signal transmission delay value is 8.9 ns,which can be applied to the working frequency of 10 MHz.Therefore,the GaN driver designed in this paper has high CMTI capacity and excellent high frequency performance.