An ON/OFF controller (124, 300, 700) for use in a power converter, wherein the ON/OFF controller produces a sequence of enabled and disabled switching cycles to regulate the output of the power converter, wherein when a cycle is enabled, a power switch may conduct current while the power switch cannot conduct current during a disabled cycle, the ON/OFF controller comprising: a drive circuit (126, 326, 726) coupled to generate a drive signal (144, 344, 444, 544, 644, 744, 844) to control switching of the power switch to control a transfer of energy from a power converter input to a power converter output; an input for receiving an enable signal (138, 338, 438, 638, 738) that includes enable events which enable or disable the power switch and are responsive to the power converter output, wherein the drive circuit (126, 326, 726) is coupled to turn ON the power switch in response to the enable events and turn OFF the power switch in response to a power switch current reaching a current limit threshold; characterized in that the ON/OFF controller further comprises a current limit threshold generator (128, 328, 728) coupled to receive the drive signal (144, 344, 444, 544, 644, 744, 844) from the drive circuit and to vary the current limit threshold in response to the enable events of the enable signal (138, 338, 438, 638, 838), wherein the variable current limit threshold increases at an increase rate at the end of each ON time of the power switch for a fixed time period or until a maximum current limit threshold (256, 356, 456, 556, 656, 856) is reached and the variable current limit threshold then decreases at a decrease rate until the current in the power switch reaches the current limit threshold or the variable current limit threshold reaches a minimum current limit threshold (258, 358, 458, 658, 8587). a drive circuit (126, 326, 726) coupled to generate a drive signal (144, 344, 444, 544, 644, 744, 844) to control switching of the power switch to control a transfer of energy from a power converter input to a power converter output; an input for receiving an enable signal (138, 338, 438, 638, 738) that includes enable events which enable or disable the power switch and are responsive to the power converter output, wherein the drive circuit (126, 326, 726) is coupled to turn ON the power switch in response to the enable events and turn OFF the power switch in response to a power switch current reaching a current limit threshold; characterized in that the ON/OFF controller further comprises a current limit threshold generator (128, 328, 728) coupled to receive the drive signal (144, 344, 444, 544, 644, 744, 844) from the drive circuit and to vary the current limit threshold in response to the enable events of the enable signal (138, 338, 438, 638, 838), wherein the variable current limit threshold increases at an increase rate at the end of each ON time of the power switch for a fixed time period or until a maximum current limit threshold (256, 356, 456, 556, 656, 856) is reached and the variable current limit threshold then decreases at a decrease rate until the current in the power switch reaches the current limit threshold or the variable current limit threshold reaches a minimum current limit threshold (258, 358, 458, 658, 8587).