碳化硅MOSFET基于栅压延时关断方法的结温监测技术研究

Research of SiC MOSFET junction temperature monitoring technology based on gate voltage delayed turn-off method

准确监测功率器件结温一直是器件厂商及应用端非常重要的一项工作。主流的温敏电参数法由于响应速度快、测量准确,被广泛地应用于各个领域。目前在硅基器件应用上已相对成熟,然而由于碳化硅器件的高开关特性及栅极氧化层缺陷,采用电参数法会产生更强烈的寄生振荡与高频EMI噪声,这对于测量器件初始温度会带来很大的误差,因此文章提出一种栅压延时关断的改进电参数法测试方案,抑制器件关断阶段的VDS振荡,通过仿真及电路应用验证,以及热阻测试对比分析,验证了这种栅压延时方案能够有效抑制波形振荡,达到准确测量器件结温的目的。

Monitoring the junction temperature of power devices accurately is very important for device manufacturers and applica‐tions.The mainstream temperature-sensitive electrical parameter method is widely used in various fields because of its fast response speed and accurate measurement.At present,it is relatively mature in silicon-based device applications.However,due to the high switch‐ing characteristics of SiC devices and the defects of gate oxide layer,the electrical parameter method generates stronger parasitic oscilla‐tion and high frequency EMI noise.This causes large errors in measuring the initial temperature of the device.Therefore,a test scheme based on the improved electrical parameter method for gate time delay was proposed to suppress the VDS oscillation at the device turn-off moment.Through simulation and circuit application verification,as well as comparative analysis of thermal resistance test,it was proved that this scheme could effectively suppress waveform oscillation and measure the junction temperature of the device accurately.