UCC28710: Schematic Review

Hello,

Functionally your schematic looks correct; however, the UCC28710 was designed for an output regulation of +/- 5 %.  1% output ripple might be too aggressive.

Also, your design looks to require 14 % duty cycle.  The controller was design to operated from a Dmax of 42.5% and peak current and frequency modulation to control the duty cycle.  This is what is know as a control law profile. 

I reviewed the control law and your design will be operating at a frequency of roughly 33 kHz.   This is at the edge of the AM and FM band. 

Fmax/dmax = 100 kHz/0.425 = fx/0.14, fx =32.64 kHz

It is recommended that when design with this device to avoid sub harmonic oscillations the frequency at nominal max load be > AM frequency + 10 kHz = 33 kHz + 10 kHz = 44 kHz.   Since this design cannot accomplish this you might want to choose another controller for your buck converter.

Since your output ripple requirement is 1% and your design could have subharmonic oscillations I would not recommend using the UCC28710 for your design.

You might consider using a UCC28C42 for your application.  You will require a gate drive transformer to drive the high side FET.

Regards,