Application of Darlington tube and typical structure of Darlington module circuit

Double tube form - Darlington tube. Current multiple: 100-1000. Large saturation voltage drop and slow speed. The dotted part in the figure below is the Darlington tube.

Figure 1-1: Darlington tube application
In practice, the Darlington module is more commonly used, which integrates the GTR, freewheeling diode, and auxiliary circuit into one module. This device was used more frequently in earlier power electronic devices. Figure 1-2 shows the typical internal structure of this device.

Figure 1-2: Typical structure of Darlington module circuit
The left side of the two diodes is the accelerating diode, and the right side is the freewheeling diode. The principle of the accelerating diode is to introduce current series positive feedback to achieve the purpose of acceleration.
The manufacturing level of this device is about 1800V/800A/2KHz, 600V/3A/100KHz (reference).