System and method for limiting input-current surge in a switching mode power supply

A power supply powered by an initial supply voltage that normally operates the power supply, comprising:

• an input voltage detector that detects a drop in an input voltage from the initial supply voltage to a voltage below a threshold, wherein said drop in the input voltage corresponds to an input voltage loss that disturbs normal operation of the power supply and return of the input voltage corresponds to return to the normal operation of the power supply;
• a power converter coupled to the input voltage detector, said power converter having a switching device that is actuated in accordance with a duty cycle;
• and
• a duty cycle adjuster that gradually increases the duty cycle of the switching device from a substantially zero value to a value that maintains a regulated output for the power supply after return of the input voltage, wherein the gradual increase of the duty cycle limits an input current surge through the switching device.