The present disclosure includes systems and methods for 100% duty cycle in switching regulators. A switching regulator circuit includes a ramp generator to produce a ramp signal having a period and a comparator to receive the ramp signal and an error signal, and in accordance therewith, produce a modulation signal. In a first mode of operation, the ramp signal increases to intersect the error signal, and in accordance therewith, changes a state of a switching transistor during each period of the ramp signal. In a second mode of operation, the error signal increase above a maximum value of the ramp signal, and in accordance therewith, the switching transistor is turned on for one or more full periods of the ramp signal.