UCC28710: Hello, i'm trying to design buck converter with ucc28710

Hello,

I do have a question how did you select your buck inductor and at what switching frequency?

This device has limitations on maximum duty cycle of less than 57.5% at the maximum switching.  The magnetizing inductance should be selected on this based on minimum input and maximum frequency.  Also your VS divider is controlling to 0.47V during the freewheeling period.

I reviewed the schematic and your VS divider is not setup correctly for 22V VS will control to 4.06V during the freewheeling period.

The other thing that could help is just evaluate with  a DC input to start until you the simulation running.

Regards,

Hello,

Please retry setting your VS divider for 22 V.  VS controls to 4.06V. 

Vout-4.06/Rvs_upper = 4.06/Rvs_lower

As long you selected the buck inductor similar to how the ucc2871x selects the primary Lm of the flyback converter.  You should be able to get this model to work.

Regards,

I did find a reference design using the UCC28700 in a buck converter.  I think you might find this useful as well.

Regards,