A system includes a two-switch H-bridge topology, which has a first switch (Q1) with a first gate drive (104) connected to control on and off states of the first switch. A second switch (Q2) has a second gate drive (106) connected to control on and off states of the second switch. An exciter winding is connected from a first node between the first switch and a second flyback diode to a second node between a first flyback diode and the second switch. A controller (116) is connected to control the first gate drive and the second gate drive in a mode wherein the first switch is always on while the second cycles as a duty-cycle-controlled switch element for the exciter winding.