A method for operating a switched mode power supply (SMPS) during a start-up sequence includes receiving an input current at a bias supply circuit while a first relay and a second relay coupled to a first side circuit within the SMPS are open, generating a first bias supply voltage based on the received input current, closing the first relay after generating the first bias supply voltage, conducting the input current through the first relay and through an in-rush resistor coupled in series with the first relay, and closing the second relay after a first time period.