A fly-back or boost stage transfers its stored energy to the energy storage capacitor of the fast driver discharge stage in a single event pulse. The charging voltage of a single flyback pulse on the capacitor is measured in real time and, if necessary, the charging current is diverted via a shunt active device or transistor, to ground, thus preventing the storage capacitor from overcharging with the risk of component damage. A series sense resistor is used to determine the presence and amount of the wasted shunt current in order that this current may be minimized by turning down the flyback energy, thus maximizing the overall efficiency.