What losses occur with the switching regulator?
Power losses occur as a result of the power needed to turn on and off the MOSFET. The MOSFET driver must bear this loss. Also, the MOSFET takes a finite time to switch to/from a conduction state to non-conduction state. Hence, power loss will be associated with this activity in the MOSFET itself. These losses are dominated by the MOSFET gate charge and the capability of the drive, in effect the energy needed to charge and discharge the capacitance of the MOSFET gate between the threshold voltage and gate voltage.
