Hello Kazuya,
The values of these two components depend on the design of the flyback system; hence, the flyback team might be able to provide you with what you are looking for. Please see the links below for a P2P compatible flyback device using TL431…
Ras
For your question on UCC2813, the internal error amplifier and reference can be bypassed. PMP2187 (schematic: www.ti.com/.../slur196.pdf) is a good example of it configured with an external error amplifier and reference. The same techniques discussed…
