The present invention provides a power conversion system, an electronic device including the same, and an integrated circuit, and relates to the field of power supplies. By arranging a second switch series branch connected to a switch series branch of a switch capacitor converter, and matching a switch in the second switch series branch and a switch in the switch series branch of the switch capacitor converter, a function of a three-level buck converter is achieved, so that the three-level buck converter and the switch capacitor converter are integrated. The quantity of switches is reduced. The volume is small. The costs are low, and high efficiency of a whole process of charging a battery of the electronic device is achieved while supplying power to a power consumption unit of the electronic device.