功率PMOS管的有源泄放驱动电路研究

Research of Drive Circuit with Active Discharging Technology for Power PMOS

为提高功率PMOS管的开关速度,分析其开关特性,提出一种能够快速开通与关断功率PMOS管的有源泄放驱动电路。通过在其栅源极间并接开关电路,并由PWM脉冲控制开关电路中电容充放电以实现并接开关管的开通与关断,迫使功率PMOS管栅-源寄生电容在开通期间快速充电,关断期间快速放电,从而快速开通与关断功率PMOS管;结合所提的驱动电路,深入分析功率PMOS管的开通与关断过程,并得出驱动电路主要元件的选取方法。将所提出的驱动电路应用于Buck变换器,结果验证了所提驱动电路的可行性及设计方法的正确性。

The switching characteristic of power PMOS is analyzed and a active discharging drive circuit is proposed.The gate-source parasitic capacitor was charged and discharged quickly during the power PMOS turn on and turn off transient through paralleling the switching circuit between the gate and the source electrode of power PMOS,which made the power PMOS turn on and off quickly.Moreover,the charging-discharging of parallel capacitor was controlled by PWM signal.Combined with the proposed drive circuit,the power PMOS turn-on and turn-off process was detailed analyzed,and the selection methods of the main components in this drive circuit were obtained.The proposed driving circuit is applied to the Buck converter,and experiment results show that the proposed circuit and theoretical analysis are valid and feasible.