Development, analysis, and implementation of an ASIC controller for single-phase power factor correction

Due to tightening regulations and industry standards on input current harmonics, significant motivation exists for the development of lower cost and higher performance solutions to power-factor-correction (PFC) control of single-phase AC-DC power converters. In this work, the nonlinear-carrier (NLC) current mode control method is generalized, offering significant advantages in the areas of simplicity, high-performance, and versatility. The control method is analyzed and modeled to increase understanding of the performance and limitations of NLC control and to facilitate design of AC-DC converters using the control method. A unique approach is presented for implementation of the NLC controller on a single application specific integrated circuit (ASIC) using standard low-cost CMOS technologies. A final ASIC design fabricated in a 1.2μ CMOS technology is described which implements a fully operational PFC controller using the NLC control method. The controller requires no external design or parameter tuning for proper operation over a wide range of operating conditions and can drive the power stage at switching frequencies up to f_s = 1MHz. Experimental results of the final ASIC design operating with a 150W AC-DC power stage are presented, demonstrating high-quality automatic input current shaping. Extensions of the ASIC controller are presented to perform on-chip output voltage regulation and to develop a “universal” NLC controller that can be easily re-configured for various power electronics AC-DC, DC-DC, and DC-AC control applications using a single hardware design.