SINGLE-STAGE AC-DC POWER CONVERTER WITH FLYBACK PFC AND IMPROVED THD

摘要

A single-stage AC-DC power converter for powering a load at a substantially constant current, and related methods and systems. The AC-DC power converter includes a high power factor correction (PFC) circuit configured in a flyback topology and operating in transition mode. The flyback PFC circuit has a PFC controller and is configured to draw an input AC current from an AC power supply. The input AC current has a first total harmonic distortion (THD). The flyback PFC circuit outputs a DC current to the load. The PFC controller is configured to sense a rectified input voltage. By multiplying the rectified input voltage sensed by the PFC controller, the input AC current drawn by the flyback PFC circuit has a second, much improved THD, which is achievable without the need of an expensive PFC controller. The rectified input voltage sensed by the PFC controller is multiplied using a Zener diode ladder.

主权项

1. A single stage AC-DC power converter for powering a load at a substantially constant current, comprising:
a flyback topology power factor correction (PFC) circuit, the flyback PFC circuit having a PFC controller, the flyback PFC circuit configured to draw an alternating current (AC) input current having a first total harmonic distortion (THD), the PFC controller configured to sense a rectified input voltage from a full-wave rectifier, the flyback PFC circuit outputting a direct current (DC) voltage and a DC current and configured to provide the substantially constant current to the load; and a passive voltage multiplier circuit configured to multiply the rectified input voltage sensed by the PFC controller, whereby multiplying the rectified input voltage sensed by the PFC controller causes the input AC current drawn by the flyback PFC circuit to have a second, improved THD.