I'm trying to understand this material from C.Basso regarding TL431 compensation (Designing Compensators for the Control of Switching Power Supplies
If you refer to pg.110, there is one example regarding TL431 based on type 2 compensator.
From the example, it stated that it require to provide 15dB at 5kHz with 50 degree phase boost. Basically, I understand all the calculation & phase boost operation using type 2 compensator.
However when it comes to pg.111, it mentioned that with Cpole = 2nF (this is based on pole value in optocoupler @ 4kHz) & C2 = 581pF, the bandwidth cannot be reached, therefore crossover frequency need to be reduced.
- From the slide above, how they know that the bandwidth cannot be reach with these Cpole (2nF) & C2(581pF) value? Any calculation example would help.
- If bandwidth cannot be reached, what will happen to the system? Any example case will be help, because it’s hard for me to imagine the impact of bandwidth to power supply system.