The UCC218915-Q1 implements a fast overcurrent and short circuit protection feature to protect the power semiconductor device from catastrophic breakdown during a fault. The DESAT pin threshold, V_DESATTH, is with respect to COM, the source or emitter of the power semiconductor device. When the driver is in the off state, the DESAT pin is pulled down by an internal MOSFET to prevent DESAT from false triggering. When the driver is in the on state, an internal current source is activated to charge an external capacitor. The UCC218915-Q1 features an internal leading edge blanking time after OUTP switches the buffer PMOS on to avoid false triggers from noise during the switching transient. When the driver turns off, the internal pulldown MOSFET discharges the voltage of the DESAT pin. A simplified block diagram of the DESAT circuit is shown in Figure 6-8. Timing diagrams showing a DESAT fault, soft shutdown, fault reporting, and fault reset are shown in Figure 6-9.

Figure 6-8 DESAT Protection

Figure 6-9 DESAT Protection Timing Diagram with Soft Shutdown