SLUAB11 November   2025 AMC23C12-Q1 , TMCS1126-Q1 , UCC21750-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Difference Between SiC and IGBT
    2. 1.2 System SCP Response Time Requirement
    3. 1.3 Different SCP Locations
  5. 2Short-Circuit Mechanism
  6. 3Short Circuit Detection Methods
    1. 3.1 Shunt-Based Method
    2. 3.2 Desaturation-Based Method
    3. 3.3 Hall-Effect Sensor-Based Method
  7. 4Test Setup
  8. 5Measurement Results
    1. 5.1 Shunt Based Measurements
    2. 5.2 Desaturation-Based Measurements
    3. 5.3 Hall-Effect-Sensor Measurements
    4. 5.4 Performance Comparison
  9. 6Conclusion
  10. 7References

5.2 Desaturation-Based Measurements

This section discusses the measurement results using the integrated desaturation detection of the gate driver UCC21750-Q1. Table 5-1 lists the crucial values of the components, resulting in a theoretical blanking time of tblk = 1μs.

Table 5-1 Component Overview of Desaturation Setup
PartValue
R230kΩ
uD20.3V
Cdesat100pF

Figure 5-4 shows the measurement results using the desaturation method. As soon as the gate-source voltage uGS reaches the threshold voltage of the SiC MOSFET at time 0ns, the current iSC starts to rise. At the same time, the voltage udesat starts to increase reaching the maximum at 1600ns, indicating an overcurrent for the gate driver. After the detection, the gate driver starts to slowly turn-off the SiC MOSFET. Due to the soft turn-off event, the drain-source voltage overshoot only reaches 940V at 1700ns.

Waveforms for Desaturation-Based Method With Soft Turn OffFigure 5-4 Waveforms for Desaturation-Based Method With Soft Turn Off