Check the saturation current of the power MOSFET
Different PFC controllers, VCC has different UVLO values, check the UVLO value of the VCC of the PFC controller used, then, VGS=UVLO, check the saturation current IDUVLO of the power MOSFET VGS=UVLO, make sure that IDUVLO is greater than the current sampling resistor The set maximum current value has a certain margin at the same time, and this maximum current value is the saturation current under the actual maximum operating junction temperature. The saturation current of high-voltage power MOSFETs with superjunction structure is generally low, and the saturation current decreases with the increase of junction temperature.
● On-region characteristics of high-voltage MOSFETs
● Transfer characteristics of high-voltage MOSFETs
● Gate charge characteristics of high-voltage MOSFETs
The lower the UVLO value of the VCC of the PFC controller, the lower the saturation current of the power MOSFET at the highest junction temperature, and the greater the possibility of linear region failure under the above conditions. The graph of Fig. 7 gives the saturation current of the power MOSFET in great detail, especially the graph of saturation current and temperature of Fig. 7(b), very important.