Before the UCC2895x controllers will start up, the following conditions must be met:

• VDD voltage exceeds rising UVLO threshold 7.3V typical.
• The 5V reference voltage is available.
• Junction temperature is below the thermal shutdown threshold of 140°C.
• The voltage on the soft-start capacitor is not below 0.55V typical.

If all those conditions are met, an internal enable signal EN is generated that initiates the soft-start process. The duty cycle during the soft start is defined by the voltage at the SS pin, and cannot be lower than the duty cycle set by TMIN, or by cycle-by-cycle current limit circuit depending on load conditions.