Gate Drive Circuits Design and Implement for AlGaN/GaN HEMT Power Transistors

• Main Authors: Che-Wei Chang, 張哲維
• Other Authors: Tsung-Lin Chen
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/56931317049935385710

碩士 === 國立交通大學 === 機械工程學系 === 100 === This thesis proposed a proper and complete high/low side gate drive circuit for GaN transistors. Unlike the conventional enhancement mode driver, this circuit designed for the depletion mode transistors, providing a negative gate-source voltage to turn off the power transistors. In the high side drive circuit, the study used a bootstrap circuit to provide a stable gate-source voltage for the power devices, and then transferred the logic signals into the appropriate control signals by the level shifter. In order to maintain high efficiency and reduce the power consumption of this circuit, the study designed a latch circuit, which combined with the level shifter to decrease the operating time. For the bootstrap capacitor charging problem, which was due to the “normally-on” property of the depletion mode transistor, the study also designed two start-up circuits to control the timing of the initial activation of the devices. Therefore, the bootstrap capacitor would have enough lead time to charge. This circuit verified by HSPICE, completed with discrete components and drove GaN transistors in 100kHz/24V driving condition. The simulation and experiment waveforms showed that the drive circuit can control the on/off state of GaN transistors normally.