someone who can tell me how to control the buck-boost use TL494 or SG3525...?
vout: 0- 50V
The Buck Boost Circuit you have attached is of Primary level. With this level of understanding, it will be very difficult and unsafe for you to try to construct Buck Boost Circuit of the specification you have mentioned as Buck Boost circuit is one of the complex circuit in smps. However, what is your input voltage?
What is your background? Have you handled smps circuits earlier? Do you know the configuration of SG3525/TL494? Please let me know, so that I can help you by assessing your understanding level.
Trying to construct circuit by only following schematic in smps is dangerous and useless.