The Dynamic Characteristics Of Power-MOSFETs In Low Temperature

With the rapid development of cryogenic power electronics, dynamic characteristics ofpower-MOSFET, which are of most importance in room temperature, have aroused theinterest of more and more researchers. This article has made a special study concentrated onthis subject.Firstly, based on the theory of the charge distribution, a new analysis on the switchingcharacteristic of power-MOSFET has been made. The variations of inter-capacitancesduring switching process have been analyzed. After a series of experiments, a gate-drivingcircuit, which can work reliably from liquid-nitrogen temperature to room temperature, hasbeen found out for the first time.According to the testing criterions of dynamic characteristics, the gate-driving signalgeneration for resistive and inductive switching test has been designed respectively. Then atesting platform has been built up after a series of improvement had been made. Based onthe measurement results, the variation rules between dynamic parameters and temperaturehave been concluded.After an analysis of the cryogenic effects inside the power-MOSFET, some importantconclusions has been made, which could help us to make a better comprehension of theswitching mechanism in low temperature. Referred to the Pspice model ofpower-VDMOSFET in room temperature, a new circuit-level model of power-VDMOSFETfrom room-temperature to low temperature has been obtained after the analysis of thevariations of inter-capacitances with temperature. Simulation result were presented andvalidated by comparison with experimental data.