SLUAAK3 January 2024 UCC256402
In some areas, the grid voltage is not stable and the grid voltage even up to two times than normal operation and is observed at the end of customer installment of the system. When there is 3 ph supply available, accidentally, the customer installs between L1 and L2 instead of L1 and N.
Another reason to cause the huge fluctuation in 1ph voltage due to the distribution transformer peak loading leading to >300VAC being common.
UCC256402A senses the bulk capacitor voltage by BLK pin to support the input over voltage protection function when grid voltage is abnormal or even up to two times than normal AC input.
UCC25640X also supports the 700V voltage rating at HV pin and HB pin to be more robust when grid voltage is unstable.