phase compensation circuit of UCC2895

Hello Nishizawa-san

I don't have a tool specific to the UCC2895 but there is a lot of general purpose loop compensation information available for example in the TI Power Supply Design seminar archive at http://www.ti.com/ww/en/power-training/login.shtml  includes a lot of control related topics including https://www.ti.com/seclit/ml/slup173/slup173.pdf  and https://www.ti.com/seclit/ml/slup277/slup277.pdf which is a good overview of the topic using a buck converter as an example - the PSFB is of course a buck derived topology so the control laws are the same. Then, for more details I'd highly recommend the document at https://www.ti.com/seclit/ml/slup340/slup340.pdf

Assuming that the UCC2895 is ground referenced on the primary side of the isolation barrier then the designer will  probably use a TL431 to bring the feedback signal across the isolation barrier - this makes some important changes to the feedback loop transfer function and these are described in http://ridleyengineering.com/design-center-ridley-engineering/49-circuit-designs/203-a21-designing-with-the-tl431-2.html   - you may have to register to access this.

There are worked examples of a loop compensation design for a PSFB in peak current mode in the data sheet for the UCC28950. This isn't exactly what you want but should give you some guidance.

Hope this helps, please let us know if you need more information.

Regards
Colin