Other Parts Discussed in Thread: UCC25640EVM-020, PMP22087
I'm designing some LLC resonant power supply with PFC and I decide to use controllers from TI.
Out voltage will be 48V and power around 800 - 900 W.
I took a look at datasheet of UCC25630x and UCC25640x families and they look like perfect controllers.
I also took a look at the suggested project on TI projects for LLC converters.
Maybe I'm wrong, but I noticed that most of those project never use the bias winding of the transformer to provide the power supply to the LLC controller and PFC controller, while the transformer has in most case the bias winding used only as BW feedback only.
I wonder if there is any reason to prefer auxiliary external supply for the controllers and what are the possible issues that I may experience if using the bias winding of the transformer to power up the controllers IC?