A power converting circuit includes a converter. The converter receives and converts an input power to provide power for a load. The converter includes a power storage unit, a switch unit, a capacitor unit, and a current sampling unit. The power storage unit includes input and output terminals. The switch unit includes first and second switches, which are series connected at a common terminal, and the common terminal is coupled to the output terminal of the power storage unit. The capacitor unit includes first and second capacitors. The first capacitor and the switch unit are parallel connected to form a capacitor-switch parallel structure. The second capacitor capacitance is more than ten times larger than the first capacitor capacitance. The current sampling unit and the capacitor-switch parallel structure are series connected to form a capacitor-sampling unit series structure. The capacitor-sampling unit series structure and the second capacitor are parallel connected.