Research And Design Of Negative Voltage Drive Technology For IGBT Gate Drive Chip

In the gate drive circuit of Insulated Gate Bipolar Transistor(IGBT)power device,the trailing current of IGBT device leads to high circuit losses during switching.At the same time,due to the high bus voltage,the system will generate a large d VCE/dt transient electrical stress at the moment of switching,and it is easy to disturb the control signal through the Miller capacitor,thereby causing the power device to be turned on by mistake.Because of its simple circuit structure and high reliability,negative voltage shutdown technology has become the first choice to solve this problem.However,the traditional negative voltage drive circuit still has many deficiencies,including multi-power supply,insufficient current drive capability,contradiction between loss and overshoot,and the fact that the conventional power supply voltage cannot guarantee the effective turn-on of IGBT devices.Therefore,the research on IGBT gate negative voltage driving technology is obviously of great significance.Based on the analysis of the structural characteristics and switching characteristics of IGBT power devices,this thesis puts forward the design requirements of the IGBT gate drive circuit.Through the study of the typical negative voltage drive circuit,four technical problems existing in the traditional negative voltage driving technology are summed up.Aiming to solve these technical difficulties,this thesis designs a new IGBT gate negative voltage drive circuit,which mainly includes two parts: one is the negative voltage generation circuit;the other is the adaptive gate drive current control circuit.Combined with the linear model,the quantitative formula of loss and overshoot is summarized,and it is pointed out that the key to solving the contradiction between low switching loss and low switching overshoot is to realize the independent regulation of output driving capability.Furthermore,a negative voltage turn-off drive circuit structure based on IGBT gate adaptive segmental current driving technology is proposed,which optimizes the trade-off relationship between loss and overshoot.Finally,based on the 0.25μm high-voltage BCD(Bipolar-CMOS-DMOS)process platform,the layout design was carried out,and the tapeout test was completed.The chip tape-out test results show that the designed new negative voltage gate drive circuit can obtain a stable negative voltage output of-2V with only a single 15 V power supply.It meets the set design indicators of single power supply,power supply voltage of15 V and strong driving capability.Compared with the traditional negative voltage drive circuit,the current overshoot is reduced by 42% and the turn-on loss is also reduced by 8%.The voltage overshoot is reduced by 42.8% and the turn-off loss is also reduced by 8.7%.A better compromise is achieved between switching losses and current and voltage overshoot.The expected design goals have been achieved.