Research On SiC MOSFET Gate Drive Circuit With Wide Temperature Range And Low Switching Loss

With the increasing progress of the semiconductor industry,Si,as a traditional semiconductor material,has been unable to meet the needs of applications in certain fields.The third-generation semiconductor material,taking SiC as an example,has gradually become a new choice.At present,China is advancing 5G,data Centers,new energy vehicles and other fields of "new infrastructure" have promising applications.As a power semiconductor device of SiC material,SiC MOSFET has the advantages of high blocking voltage,low on-state resistance,fast switching speed and high operating junction temperature.To make full use of its advantages,i t is necessary to design a matching gate drive circuit to ensure good switching transient performance of the SiC MOSFET.This paper focuses on the main problems of the SiC MOSFET gate drive circuit,such as the improvement of the drive method,the calculation of the gate resistance and the characteristics of the drive circuit with temperature.First,this paper analyzes the switching process of SiC MOSFET,describes the switching process in detail,compares the dynamic parameters of Si power MOSFET and SiC power MOSFET,and puts forward the specific requirements of SiC MOSFET drive circuit.The influence of gate resistance and driving voltage on driving characteristics is analyzed.On this basis,a variable gate resistance driving circuit is proposed,and the working principle and circuit design of the circuit are described in detail.Secondly,in order to further optimize the proposed driving circuit,the calculation method of the gate resistance is derived.This derivation takes the double-pulse test circuit considering parasitic parameters as the model,and aims at reducing the voltage and current oscillations and switching losses in the switching process.The circuit is analyzed in frequency domains.The relationship between voltage and current overshoot and switching loss is deduced,which further proves that a single resistance cannot solve the contradiction between oscillation and switching loss.The relationship between gate resistance and voltage-current oscillation is established through formula derivation and simplification,which provides a basis for quantitative calculation for the selection of suppression of oscillation resistance.Thirdly,high-temperature design of the drive and protection circuits.The temperature characteristics of passive components such as resistance,capacitance,and inductance of discrete components are analyzed.The detailed analysis of the switching state of the transistor with temperature changes provides a basis for the selection of high-temperature drive circuit devices.The topology of the high-temperature drive circuit is designed,and the under voltage lock out protection and overcurrent protection of the SiC MOSFET are designed on the basis of satisfying the drive,and the circuit working principle is analyzed in det ail.Finally,through simulation and hardware experiments,the switching loss reduction and oscillation suppression of the variable gate resistance drive circuit were verified.The double-pulse test PSpice simulation was performed on the high-temperature drive circuit,under voltage lock out protection and overcurrent protection,and the design was analyzed.The driving and protection characteristics at different temperatures provide a driving circuit solution for high-temperature applications of SiC MOSFET.