A DC-DC power converter employs a full bridge series resonant converter topology with a resonant tank and two transformers, one before and one after the resonant tank, to obtain a high voltage (e.g., approximately 300V, approximately 1500V or greater) output from a relatively low voltage (e.g., approximately 9V-16V) input, for instance an input from one or more battery cells. DC-DC power converter is operable to output high voltage (e.g., around 300V, 1500V or higher) short duration pulses (e.g., tens of nanoseconds or less). A burst mode control technique provides as good regulation characteristics at light loads. Instead of turning OFF the active switches during an OFF period, the switches are operated at a different frequency (e.g., higher frequency) during the OFF period than a frequency at which the switches are turned ON during the ON period. Auxiliary loads can also be supplied.