The invention relates to a switching regulator for operating luminaires, comprising a control circuit (4). The control circuit (4) is designed to operate, by triggering the switch (5) that is coupled to a coil, the switching regulator (3) in a limit mode of operation when the load generated by the luminaire (2) is so high that the resulting switching-off threshold exceeds a predefined minimum switching-off value, and operate the switching regulator in a discontinuous mode of operation at the minimum switching-off value when the load generated by the luminaire (2) is so low that the switching-off threshold in a limit mode of operation would lie below the predefined minimum switching-off value. The signal representing the current is fed to the control circuit (4) in both the limit mode of operation and the discontinuous mode of operation without being subjected to any external mean value generation.