JAJSE40A October 2017 – February 2018 UCC28780
The UCC28780 operates with cycle-by-cycle primary-peak current control. The normal operating range of the CS pin is 0.15 V to 0.8 V. If the CS-pin voltage exceeds the 1.2-V over-current level, any time after the internal leading edge blanking time (tCSLEB) and before the end of the transformer demagnetization, for three consecutive PWML cycles, the device stop switching, RUN pin goes low, and 1.5-s recovery time is initiated. Similar to OVP, OPP, and SCP, only the UVLO-cycle of VDD is active, there are no test PWML pulses at all. After the 1.5-s time-out is completed and VVDD reaches the next VDD(OFF), a normal start sequence begins.