Methods and systems for providing electrical power using an isolated DC-DC converter include: using a power supply to provide multiple amplitudes of open loop current to a primary side of a transformer. The amplitudes are selected to increase stepwise, at predetermined times, to ramp a voltage across output terminals connected to a secondary side of said transformer so that after said power supply provides a maximum open loop current amplitude, said voltage reaches a threshold sufficient to enable a closed loop controller connected to said output terminals to send a feedback signal to said primary side. The threshold voltage is insufficient to fully power said output terminals. The feedback signal is selected to control said power supply to increase current to said primary side at closed loop current levels until said output terminals are fully powered.