Abstract: A Boost power factor correction (PFC) converter operating in pseudo continuous conduction mode (PCCM) is analyzed and side-by-side voltage and current control loops is proposed. In order to extend the load power range of the conventional Boost PFC converter operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), a control strategy to adjust the reference current with respect to the load is designed. The input current and PF expression of the tri-state PCCM Boost PFC converter is also derived. To improve the input power factor (PF) of the tri-state PCCM Boost PFC converter with sinusoidal reference current control strategy over whole input voltage range, the non-sinusoidal reference current control strategy is proposed. Besides, the frequency domain analysis based on small-signal mode is given. Finally, the tri-state PCCM Boost PFC converter prototype is built and the experimental results verify the analysis results.