In one aspect, an apparatus for use in a wellbore is disclosed, including: an inlet; an outlet; and a variable flow restriction configured to provide a predetermined constant pressure drop between the inlet and the outlet in response to a range of inlet flow rates. In another aspect, a method for providing a fluid flow within a wellbore is disclosed, including: providing the fluid flow to an inlet; restricting the fluid flow to provide a predetermined constant pressure drop between the inlet and an outlet in response to a range of fluid flow rates; and providing the fluid flow to the wellbore from the outlet.