A DC-DC converter (100) includes an inductor (110), a switch module (MP, MN), a pull-up circuit (1 20) and a pull-down circuit (1 30). The inductor (1 10) has a first node and a second node, and the second node is coupled to an output node (Nout) of the DC-DC converter (1 00). The switch module (MP, MN) is arranged for selectively connecting an input voltage or a ground voltage to the first node of the inductor (110) according to a driving signal. The pull-up circuit (120) is arranged for selectively providing a first current to the output node (Nout) of the DC-DC converter (100). The pull-down circuit (130) is arranged for selectively sinking a second current from the output node (Nout) of the DC-DC converter (100). In addition, at least one of the first current provided by the pull-up circuit (120) and the second current sunk by the pull-down circuit (130) is determined based on an inductor current flowing through the inductor (110).