Negative voltage turn-off driving circuit based on wide bandgap power device

Abstract

The invention relates to a negative voltage turn-off driving circuit based on a wide bandgap power device. The circuit comprises an auxiliary power supply VDD, a bootstrap resistor RBoot, a bootstrapdiode DBoot, a bootstrap capacitor CBoot, a capacitor CVDD, a driver U1, a driver U2, a freewheeling resistor RFw, a bias capacitor CBias, a voltage stabilizing tube DZ1 and a voltage stabilizing tubeDZ2. The negative voltage turn-off driving circuit based on the wide bandgap power device is used for avoiding the bridge type direct connection problem and the self-excited oscillation problem of awide bandgap power semiconductor in a bridge type circuit due to bridge type crosstalk. The driving circuit has a gate-source negative voltage turn-off capability, mistaken conduction due to fact thatgate-source voltage is higher than threshold voltage in turn-off period is avoided, on the premise that the auxiliary power supply of the driving circuit is not increased, it is guaranteed that the driving circuit can achieve negative voltage turn-off, meanwhile, the negative voltage turn-off capacity is not affected by the duty ratio, and the misconnection of the power device caused by crosstalkis avoided.

Description

technical field [0001] The invention belongs to the technical field of power electronic circuits, and relates to driving circuits of third-generation wide bandgap semiconductors represented by SiC MOSFETs and GaN HEMTs, in particular to a negative voltage turn-off driving circuit based on wide bandgap power devices. Background technique [0002] figure 1 Shown is prior art scheme one [1] . This technical solution adds two auxiliary power supplies V to the traditional drive circuit SS_H and V SS_L , two auxiliary capacitors C DD_H and C DD_L Realize gate-source negative voltage shutdown of power devices. Reliable turn-off negative voltage can prevent the gate-source voltage from exceeding the threshold voltage during turn-off due to bridge crosstalk and self-excited oscillation of power devices, thereby avoiding false conduction of the switch tube. [0003] figure 2 yes figure 1 The driving signal and gate-source voltage signal corresponding to the switching tube in...

AI Technical Summary

Problems solved by technology

The size of the drive circuit depends on the size of the auxiliary power supply. The double auxiliary power supply realizes the negative voltage shutdown of the drive, which greatly increases the size of the drive circuit.

[0011] 2) Additional auxiliary power supply leads to increased loss of the drive circuit

[0012] 3) Due to the common ground factor, the solution is not suitable for bootstrap drive circuits

In the start-up phase, the gate-source forward voltage may be higher than the forward voltage safety voltage, resulting in gate-source breakdown, and there is no negative voltage shutdown capability

[0022] 2) The gate-source turn-off negative voltage is not only affected by the Zener diode, but also by the duty cycle of the driving signal. When the duty is small, the driving scheme has no negative voltage turn-off capability

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