UCC28730-Q1: UCC28730QDRQ1的使用问题

您好

Functionally the schematic looks correct.  I would recommend using an RCD clamp vs a TVS clamp.  It helps dampen the ringing at the switch node which will improve EMI and power stage performance.

The output voltage is sense and controlled by VS pin through the resistor divider and the secondary to aux turns ratio.  The device will then adjust the frequency and peak current to maintain a VS voltage of 4.04 V during the transformer demanganization period.   

Vs = Vout*Na/Ns*(R56/(R56+R58)

In regards to designing with the UCC28730 you can use the UCC28730 excel design tool which can be found at the following link.

https://www.ti.com/tool/download/SLUC579

The excel tool can be used to calculate the input and output bulk capacitance the design requires.  These capacitors are selected based on allowable output ripple voltage of your design.

The excel tool will calculate the required turns ratio of for the transformer; as well as, the transformers RMS currents.  You then would give this information to a magnetic designer and have them design the transformer for you.

If you want to design the transformer yourself, I would recommend going to mag-inc website. They have many application notes that you might find useful. www.mag-inc.com