GaN组合开关电路及其驱动技术研究

Driving technology of GaN HEMT and its application

基于氮化镓的高电子迁移率场效应晶体管(GaN HEMT)具有电子迁移率高、耐高温和极低的寄生电容等诸多特点而成为开关变换器领域关注的焦点。限于目前的制造工艺,基于氮化镓材料的MOS开关器件更容易做成耗尽型,针对耗尽型GaN HEMT器件的负电压关断特性,结合其应用于开关变换器的上电短路问题,提出一种GaN HEMT器件与增强型MOSFET的组合开关电路,可实现对耗尽型GaN HEMT器件的开、关控制及可靠关断,但其关断速度不够快。为此,提出一种快速关断GaN HEMT器件的驱动电路,并得到了进一步提高GaN HEMT器件开关速度的改进电路,可实现对耗尽型GaN HEMT器件快速可靠关断。实例及实验结果验证了所提出电路的可行性。

GaN HEMT is the focus of the switching power supply due to its high mobility,high temperature and low parasitic capacitance. Limited to the fabrication process,the GaN switching device only can be made to depletion-mode switching device. Aimed at the negative voltage turn-off characteristic and the short-circuit problem of the depletion-mode GaN HEMT device,a combination switch with GaN HEMT and enhanced MOSFET is proposed,the turn-on and turn-off control for the depletion-mode GaN HEMT device can be realized,the GaN HEMT device can be turned off reliably,but the tutn-off speed is not fast. Thus,the drive circuit of the GaN HEMT device is proposed,an improved circuit for increasing the tutn-off speed of the GaN HEMT device can be obtained,and fast and reliable turn-off for the Depletionmode GaN device can be realized. Experiments results show the feasibility of the proposed circuit.