A power management system includes a first switch, a second switch, and a controller coupled to the first and second switches. The first switch has a first transfer terminal. The second switch has a second transfer terminal. The controller controls power conversion by turning on a third switch periodically. The first and second transfer terminals and a third transfer terminal of the third switch are coupled to a common node. The resistance between the first transfer terminal and the common node, the resistance between the second transfer terminal and the common node, and the resistance between the third transfer terminal and the common node are substantially equal to zero.