Soft start

An electronics term describing any circuit which is current limited during initial power up. Many devices such as DC/DC converters will consume a large initial current that can cause voltage fluctuations and affect the proformance of other circuits connected to a common power supply. To counteract this issue, components can be added is series to throttle back the current initially as the device comes online.

This type of circuit is also used to start lamps whereas a cold filament (i.e. tungsten) has a much lower resistance and allows a large inrush of current. This inrush creates a temperature gradient that causes thermal strain and therefore, stress on the material. Also, the higher initial current can cause damage to other components like switches if they are not rated for the initial high current.