Unlike existing single-stage AC/DC converter with uncontrolled intermediate bus voltage, a new single- stage AC/DC converter achieving power factor correction (PFC), intermediate bus voltage output regulation and output voltage regulation is proposed. The converter is formed by integrating a boost PFC converter with a two-switch clamped flyback converter into a single power stage circuit. The current stress of the main power switch is reduced due to separated conduction period of the two source currents flowing through the power switch. A dual-loop current mode controller is proposed to achieve PFC, and ensure independent bus voltage and output voltage regulations. Experimental results on a 24 V/100 W hardware prototype are given to confirm the theoretical analysis and performance of the proposed converter.