IGBT modules block overcurrent by controlling the gate

When an overcurrent flows, the gate is controlled to block the overcurrent (protection), making it possible to "implement safely without damaging the device."

In the figure, once the thyristor is triggered, the IGBT cannot be turned off because the thyristor will not automatically extinguish the arc due to the blocking signal of the gate, etc., resulting in damage to the component due to overcurrent (this is called "electrical latching").

In order to prevent this "electrical latch-up phenomenon" in IGBT, the following technologies are fully utilized.

1) Use a structure that is less likely to cause "electrical latch-up" (reduce the resistance between the base and emitter in Figure 1-5).

2) Controlling the hFE of the PNP transistor by optimizing the thickness and impurity concentration of the n-buffer layer.

3) Control the hFE of the pnp transistor by introducing factors that reduce the lifetime.

Through the above technologies, IGBT has achieved high-speed switching, high withstand voltage, and large capacity while maintaining the maximum tolerance to fully protect against overcurrent (short circuit), and has been commercialized.