This application provides a conversion circuit, a switching power supply, and an electronic device. The conversion circuit mainly includes a first branch circuit and a second branch circuit. Input sides of the first branch circuit and the second branch circuit are connected in series, and output sides of the first branch circuit and the second branch circuit are connected in parallel; or input sides of the first branch circuit and the second branch circuit are connected in parallel, and output sides of the first branch circuit and the second branch circuit are connected in series. This implementation helps improve efficiency of the conversion circuit. When an inductor is disposed in the conversion circuit, a size of the inductor is further reduced, to improve integration.