基于液压模型的功率MOSFET有效输出电容测试方法

Test method for effective output capacitance of power MOSFET based on the hydraulic model

输出电容是影响功率MOSFET开关损耗的重要参数.在开关应用中,根据输出电容Coss来确定器件的开关损耗具有一定的局限性.为了准确地评估器件的开关损耗,研究了功率MOSFET的有效输出电容Coer和Cotr及其测试方法.首先,以液压模型理论为基础阐述了器件参数Coer和Cotr的具体含义,并完成相应的测试电路设计.然后,建立了基于测试电路的数值计算模型;为了保证测试精度,模型中充分考虑了电压测试电路产生的负载效应.最终,采用该方法对器件的有效输出电容进行测试和计算.实验结果表明,该测试方法能对功率MOSFET的有效输出电容进行可靠测试.

Output capacitance is a critical parameter that affects switching losses of power MOSFET.In switching applications,it has some limitations to determine the switching losses of devices according to the output capacitance Coss.In order to accurately evaluate the switching losses of power MOSFET,the effective output capacitance Coer & Cotr and their test method were studied.Firstly,based on the hydraulic model theory,the specific meaning of device parameters Coer & Cotr was explained and the corresponding test circuit was designed.Then,a numerical calculation model was established based on the test circuit.To ensure the test accuracy,the loading effects produced by the voltage test circuit were fully considered in the model.Finally,this method was used to test and calculate the effective output capacitance of the device.The experimental results show that this method can reliably test the effective output capacitance of power MOSFET.