一种抑制SiC MOSFET电压电流过冲的有源门极驱动电路

An Active Gate Driver Circuit for Suppressing Voltage and Current Overshoots of SiC MOSFETs

相较于Si MOSFET,SiC MOSFET的高电子迁移率使其能支持更高的开关速度,但与此同时会产生更大的电压、电流过冲,影响其应用的可靠性。提出了一种用于抑制SiC MOSFET漏源电压vds与漏极电流id过冲的有源门极驱动(AGD)电路,通过检测vds和id变化率(dvds/dt和did/dt),利用高速模拟反馈回路控制门极驱动电流的方式来调节dvds/dt与did/dt,进而减小vds与id过冲。此外,将AGD方案拓展到电流源驱动电路,提出了电流源有源门极驱动(ACGD)电路。相较于传统门极驱动(CGD),ACGD方案同时具有更快的开关速度与更小的电压、电流过冲。基于双脉冲电路对比了CGD与ACGD的不同效果,在采用ACGD电路后,电流过冲减小了20%,延时减少了30 ns;电压过冲减小了约7%,延时减少了60 ns,电压上升速率提高了约44%。

Compared with Si MOSFETs,SiC MOSFETs have higher switching speed because of the higher electron mobility.However,it may cause serious voltage and current overshoots,which affects the reliability in application.An active gate driver(AGD)circuit for suppressing drain-source voltage v_(ds)and drain current i_d overshoots of SiC MOSFETs was proposed.After detecting the v_(ds)and i_d variation rates(dv_(ds)/dt and di_d/dt),a high-speed analog feedback circuit was used to adjust dv_(ds)/dt and di_d/dt by controlling the gate drive current.As a result,the overshoots of v_(ds)and i_d could be successfully reduced.Besides,the AGD scheme was extended to current source driver circuit,and an active current source gate driver(ACGD)circuit was proposed.Compared with conventional gate driver(CGD),ACGD scheme achieves both faster switching speed and smaller voltage and current overshoots.The double pulse circuit was used to compare the different effects of CGD and ACGD.After using ACGD circuit,the current overshoot is reduced by 20%and the delay is reduced by 30 ns.The voltage overshoot is reduced by about 7%,the delay is reduced by 60 ns,and the voltage slew rate is increased by about 44%.