Semi-Digital Interleaved PFC Control with Optimized Light Load Efficiency

A control structure for an interleaved power factor correction (PFC) rectifier with smart combination of analog and digital control parts is presented in this paper. Analog technique is employed to accomplish high control bandwidth while digital control is used for parts of lower dynamic demands. This results in low microcontroller costs though the system is kept flexible. Particularly, the control strategy can be adapted depending on the operation point. Since the light load performance is in recent focus of interest, appropriate algorithms to improve light load efficiency were implemented on a prototype system and are briefly described in this paper. The effectiveness of the proposed semi-digital control approach is verified by experimental results.