Circuit of uninterrupted power supply

The invention discloses a circuit of an uninterrupted power supply. The circuit comprises an electric supply input module, a PFC module, an inverter module, a charger module and a battery pack module, wherein the output end of the electric supply input module is connected to the input end of the PFC module; the PFC module comprises a first coupling inductor L4, a first switching device Q1, a second switching device Q2, a third switching device Q9, a fourth switching device Q10 and a busbar capacitor C1, the L4 comprises a first coil and a second coil, the first end of the first coil and the first end of the second coil are connected to the output end of the electric supply input module, the first end of the Q1 and the first end of the Q9 are connected to the anode of the C1, the second end of the Q1 and the first end of the Q2 are connected to the second end of the first coil, the second end of the Q9 and the first end of the Q10 are connected to the second end of the second coil, and the second end of the Q2 and the second end of the Q10 are connected to the cathode of the C1; the input ends of the inverter module and the charger module are connected to the output end of the PFC module; and the output end of the battery pack module is connected to the input end of the PFC module.