Supercharged internal combustion engine and method of operating such an internal combustion engine

The engine has two cylinder groups equipped with a separate exhaust-gas line, where both lines are connected to each other. The gas lines include two exhaust-gas turbochargers with two turbines that are connected in parallel. A separate shut-off unit (16) is provided in downstream of one turbine with one line such that cross section flow of the line is changed in an infinitely variable way during a two-stage operation.