An Overview of Stability Improvement Methods for Wide-Operation-Range Flyback Converter with Variable Frequency Peak-Current-Mode Control

Recently, flyback converter with Universal Serial Bus Power Delivery (USB-PD) specification is widely used in low-power adaptor application. However, the wide output-voltage- range operation of USB-PD makes the stability issue of flyback converter more severe. This paper provides a brief overview of two stability improvement methods for variable-frequency peak-current mode (VFPCM) controlled flyback converter while possessing the variable frequency characteristic for high efficiency and completely interprets those detail techniques. Simulation validates the performances of the two methods. Furthermore, a control circuit and a flyback converter are built for experimental validation of NVFPCM control with constant crossover frequency. Finally, some comments are also summarized.