Flyback-forward power factor correction circuit with line-frequency ripple suppression

A flyback-forward converter with power factor correction and line ripple suppression is proposed. The topology combines forward and flyback circuits with a post regulator. To maintain a high power factor, the flyback circuit delivers the major output power, while the output voltage is controlled by the post regulator with fast response to suppress line-frequency ripple without the use of a high voltage bulk capacitor or current sensor on the primary side. The circuit features high power factor and low output line-frequency ripple in discontinuous conduction mode. A theoretical analysis and experimental results are presented.