The front end uses comparator U2, and the boost circuit will be enabled only when the control signal is higher than 0.5V.
R2 and R3 are used to set the output voltage, and R 1 and R4 are used to adjust the feedback voltage, thus controlling the output. The specific parameters need to be adjusted according to the parameters of your BOOST chip.
I just drew a sketch, because you have to drive 50W, so you need to choose a higher power boost circuit. You'd better add a MOS switch at the input front end, which requires a step-down circuit to generate 0.5V.