An adaptive current limit circuit is provided in a power converter to achieve a fixed output current limit over duty cycle. In a converter including a high side switch, a low side switch coupled to the high side switch at a switch node, and an inductor coupled between an input voltage source and the switch node, the adaptive current limit circuit is coupled to receive the high side control signal and configured to generate an adaptive current limit threshold that varies based at least in part on the duty cycle of the high side switch.