The current invention provides a power supply that includes an igniter that generates an ignition voltage for igniting a DC lamp; an auxiliary power stage that outputs an auxiliary voltage for sustaining sufficient current in the DC lamp after the DC lamp is ignited; a voltage conversion stage coupled to the auxiliary power stage and generating a voltage at a level that is higher than the auxiliary voltage; and a switch that couples the auxiliary voltage to the DC lamp and the voltage conversion stage for a predefined period of time.