LM5156: Is there any method the output voltage based on different input voltage?

Hi all, I am new to use this LM5156, since I want to make a non isolated booster circuit using LM5156, input voltage is 15~21V, and output we desired it may change from 24V to 29V due to different input voltage.

I was check that the output voltage is modified by FB pin with voltage divider from output voltage, so I try to change the FB pin pick voltage from output to input. However, the result of output voltage is swing very high (sometime change to >60V suddenly).

May I know is this possible to using input voltage to reference the output voltage? is there any additional circuit I need to build? thanks!