(2) Because the current flowing through the IGBT is detected by other circuits, and only the current flowing through the IGBT is detected, it is possible to have a certain impact on the efficiency of the use of the IGBT, such as the early protection sometimes appears when the IGBT is in the safe working area;
The response of the control circuit and the detection circuit to the current signal should be fast, generally from the occurrence of overcurrent to the reliable shutdown of the IGBT should be completed within 10μS;
④ When the overcurrent occurs, the TLP250 gets the turn-off signal from the controller and applies a negative voltage to the gate of the IGBT to make the IGBT hard turn off. The du\/dt of this main circuit is much larger than the normal switching state, causing the voltage applied to both ends of the IGBT to rise a lot, and sometimes it may cause IGBT breakdown.