The present invention discloses a switching regulator, which comprises: a first and a second transistors electrically connected with each other; a pulse width modulation control circuit for turning ON and OFF the first transistor and turning ON the second transistor; and a current source control circuit for controlling the second transistor so that the second transistor becomes a current source, wherein the second transistor has only two states: ON and low current, and wherein when the first transistor is ON, the second transistor is in the low current state; and when the first transistor is OFF, the second transistor is ON or in the low current state.