Flyback AC-to-DC converter

摘要

Techniques and corresponding circuitry and drivers are disclosed for improving power factor (PF) and total harmonic distortion (THD) of a flyback power factor correction (PFC) topology operating in transition-mode. In one or more embodiments, the PF and THD are improved by correcting the on-time of the switching element of the flyback PFC topology to actively shape the wave of the PFC input current. In some embodiments, the on-time is corrected using a phase-lock-loop module that synchronizes with the rectified input line voltage signal and a output regulator module that corrects the switch on-time. The control may be implemented using a digital or an analog controller.

主权项

1. A device, comprising:
a phase-lock-loop (PLL) module configured to synchronize with a rectified line voltage signal input to a flyback converter to power a load, and to detect changes in phase of the rectified line voltage signal; and an output regulator module configured to regulate at least one of output current, output voltage, and/or output power to the load, using an on-time control signal that reflects a correction factor based on phase variation in the rectified line voltage signal detected by the PLL module, wherein the on-time control signal controls switching of the flyback converter; wherein the PLL module is configured to synchronize by measuring at a sampling period Tsampling a value of the rectified line voltage signal, and adjusting the sampling period Tsamplinq based on changes in frequency of the rectified line voltage signal.