A control circuit for a switched mode power supply and a related method are provided for controlling switching elements in a power train of a switched mode power supply. The control circuit comprises a mode controller to monitor the output current to determine whether the output current exceeds a current threshold. The mode controller controls the switching controller to generate the switch control signals. When the current exceeds the current threshold, the power train operates in a continuous conduction mode, and when the output current has fallen to or below the current threshold, the operation of the power train is changed from the continuous conduction mode to a pulse skipping mode. The pulse skipping mode is entered from the continuous conduction mode and involves determining the amount of energy stored in a secondary circuit of the power train.