The present document relates to Direct Current (DC) to DC power converters. In particular, the present document relates to DC to DC power converters which comprise one or more bipolar transistors as power switches. A control circuit configured to control a power switch of a switched-mode power converter is described. The power switch comprises a bipolar transistor. The control circuit is configured to determine an indication of a time instant, at which the power switch is switched off; and to adjust a basis current for controlling the power switch based on the determined indication of the time instant.