A control circuit for controlling a switching converter having a low quiescent current. The control circuit has an error amplifying circuit, an on time generator, a first comparing circuit and a second comparing circuit. When the switching converter operates in a light load operation mode, the error amplifying circuit and the on time generator are deactivated. Meanwhile, the first comparing circuit compares a current sensing signal indicative of inductor current with a current reference signal to provide an off time control signal during an on state of a low side switch to determine an on moment of a high side switch. The second comparing circuit compares the voltage feedback signal with a voltage reference signal to provide an on time control signal to determine an off moment of the high side switch.