基于栅极限流的SiC MOSFET栅电荷测试方案

Measurement Method for Gate Charge of SiC MOSFET Based on Gate Current Limiting

SiC MOSFET是一种高性能的电力电子器件,其开通/关断过程中积累/释放的栅电荷Q_(g)对MOSFET的开关速度、功率损耗等参数有重要影响。通常采用在栅极设置恒流源驱动,对时间进行积分的方法来测量Q_(g)。为了降低驱动复杂度,提高测试结果精度和可视性,基于双脉冲测试平台的感性负载回路,改用耗尽型MOSFET限制栅极电流实现恒流充电,对SiC MOSFET进行测试。同时利用反馈电阻将较小的栅极电流信号转换为较大的电压信号。实验结果表明:在误差允许范围(±5%)内该测试方案能较为准确地测得SiC MOSFET的Q_(g),测试结果符合器件规格书曲线。

SiC MOSFETs are high-performance power electronic devices.The parameters of MOSFETs such as switching speed and power loss are greatly influenced by the gate charge Q_(g) that is accumulated or released during the on/off process.The Q_(g) is usually measured by setting up a constant current source drive at the gate and integrating the time.To reduce the drive complexity while improving test result accuracy and visibility,SiC MOSFETs were tested based on the inductive load loop of the double-pulse test platform,and depletion-type MOSFETs were used instead to limit the gate current to realize constant-current charging.A feedback resistor was also used to convert a smaller gate current sig-nal into a larger voltage signal.The experimental results show that the test method is capable of accurately measuring the Q_(g) of SiC MOSFETs within the permitted error range of±5%,and the test results align with the device specification curves.