Because of the high voltage output and a limited design margin on the output capacitor, output overvoltage protection is essential for PFC circuits. The UCC28070A implements OVP through the continuous monitoring of V_VSENSE. In the event V_VSENSE rises above 106% of regulation (3.18V), the GDx outputs are immediately disabled to prevent the output voltage from reaching excessive levels. Meanwhile the CAOx outputs are pulled low to ensure a controlled recovery starting from 0% duty-cycle after an OVP fault is released. Once V_VSENSE has dropped below 3.08V, the PWM operation resumes normal operation.