Using inductive kick along with zener clamp to generate the above-the-rail gate voltage needed by a high-side N-MOSFET switch to turn on. Note that the various current limiting resistors must be chosen carefully depending on the kick inductor size and N-MOSFET gate capacitance (and the switching frequency/duty cycle?) so as to store enough energy to charge the gate fully and quickly on each rising edge, but not so much that the NPN cannot clamp the inductor from ringing during the off periods.
I think.
