Hi Brant,
Optimizing the efficiency at a different switching frequency will require some tuning of the three items you mentioned (transformer design, FET selection, and timing of the SR FETs.) Lower Rdson is not necessarily better for higher frequency…
Hi Peter,
U3 can be eliminated, as the UCC2897A is capable of driving the primary FETs. Only be careful that the UCC2897A is not too far away from the FETs in the layout.
U1 and U4 are needed. These two drivers buffer the synchronous rectifier FETs…
Hi Peter,
Sorry, but no EMI test data is available for this design. Also, this reference design does not include an EMI filter, so it will not pass EMI by itself.
thanks, Brian
Hi Nicholas,
The UCC28700 operates with a control law that includes quasi resonant switching. Essentially, the controller turns on the primary FET during the valleys of the quasi-resonant ring on the switch node. The part is always switching on the…
It really depends on your design goals of cost vs. efficiency. If you want to design for lowest cost, I recommend using the UCC28704 PSR Flyback controller. If you want to design for highest efficiency and highest power density, I recommend our UCC28782…
