The MOSFET is turned on when V_DS is the lowest after the inductor current has reached zero, resulting in the lowest turn-on losses.
Turning on the MOSFET in the second valley limits the switching frequency without compromising on efficiency.
Default settings: 24V DC input - 47V DC output
Input power: 11.47W
Output power: 11.23W
Efficiency: 97.9%
Frequency: 102kHz
Load
VDC IN