This paper presents a digital signal processor based control of an AC/DC converter with nearly unity power factor. Normally, the output voltage of a single-phase AC/DC converter comprises a voltage ripple with twice line-frequency. This affects the voltage control loop and leads to the converter input current distortion. The purposed method is designed to avoid the effect of the output voltage ripple. To verify the proposed control method, MATLAB/Simulink is used for system simulation. A hardware prototype is setup. A low cost digital signal processing chip dsPIC30F4011 is employed as a digital controller to control a CUK AC/DC converter. The converter specifications are 48V output voltage and 250W output power. From the simulation and the experimental results shown that the input current distortion of the purposed system is reduced and lower than the AC/DC converter that controlled by the conventional proportional-integral controller.