Power factor correction PFC circuit and current sampling device thereof

The invention discloses a power factor correction PFC circuit and a current sampling device thereof. The PFC circuit comprises first to fourth MOS transistors and a driving control device. The current sampling device comprises a current transformer which is provided with a first primary winding, a second primary winding and a secondary winding. The first primary winding is connected between the first MOS transistor and the third MOS transistor. The second primary winding is connected between the second MOS transistor and the fourth MOS transistor. The secondary winding is used for inducing current of the first primary winding or the second primary winding so as to generate induced current. The current sampling device also comprises a detection module of which the first input end and the second input end are respectively connected with the two ends of the secondary winding and the output end is connected with the driving control device. The detection module is used for generating a current detection signal according to induced current so that the driving control device is enabled to control the PFC circuit according to the current detection signal and the positive and negative half cycle of current sampling can be realized by only one current transformer, and thus the circuit structure is simplified, circuit cost is reduced and stability of the system is enhanced.