UCC28950: Control phase shift in A/B and C/D

Hello Amelie

There is a description of the PSFB at https://training.ti.com/topology-tutorial-what-phase-shifted-full-bridge and the animation embedded in the power point presentation at /cfs-file/__key/communityserver-discussions-components-files/196/1526.Animation.pptx may give you a better idea of how the phase shifting works. Normally the phase shift can go from 0deg to a little less than 180deg. A burst mode is usually used to avoid very inefficient operation at close to 0deg and the upper limit is usually set by the Dmax limits of the controller - maybe about 170deg or so for Dmax of 95%.

I'd also suggest you use the UCC28951 instead of the UCC28950. The UCC28951 device is an enhanced version of the UCC28950. It is a fully compatible drop-in replacement for the UCC28950. Refer to application note SLUA853 at http://www.ti.com/lit/an/slua853/slua853.pdf for more details. The UCC28951 is typically the better choice, especially for applications where the system may have to operate simultaneously at a duty cycle> 90% and current limit.

Regards

Colin