Other Parts Discussed in Thread: UCC256301
input is turned off, the voltage on the large electrolytic capacitor will begin to drop, and at this time the power supply will continue to work until the big electrolysis. When the voltage on the capacitor falls to about 200V, the chip stops working, because the voltage on the large electrolytic capacitor is only 200V, which leads to the difference between the resonant parameters and the normal working parameters, and may enter the ZCS region. in order to avoid this phenomenon, some chips can be dealt with by the minimum frequency limit, but UCC256301 does not see this function and does not know how to deal with this problem.