Abstract: A SMPS has a switch, an inductor, a zero current detection circuit for detecting the current flowing through the inductor, a load judgment circuit and a control signal generating circuit. The load judgment circuit is coupled to the zero current detection circuit and provides a plurality of status signals based on a zero current duration of the inductor current. The control signal generating circuit generates a control signal which transits from a first state to a second state when a feedback signal satisfies a preset condition, and the control signal transits from the second state to the first state after an on time of the switch, and wherein the on time is controlled based on the plurality of status signals.

Abstract: A SMPS has a switch, an inductor, a zero current detection circuit for detecting the current flowing through the inductor, a load judgment circuit and a control signal generating circuit. The load judgment circuit is coupled to the zero current detection circuit and provides a plurality of status signals based on a zero current duration of the inductor current. The control signal generating circuit generates a control signal which transits from a first state to a second state when a feedback signal satisfies a preset condition, and the control signal transits from the second state to the first state after an on time of the switch, and wherein the on time is controlled based on the plurality of status signals.