SINGLE-STAGE PFC + BALLAST CONTROL CIRCUIT/GENERAL PURPOSE POWER CONVERTER

摘要

Two switching half-bridges are operated to achieve constant power delivered to a resonant load while achieving a high power factor. A half-bridge connected to a circuit input draws a sinusoidal current that is in phase with the input voltage to achieve the high power factor. The two half-bridges are composed of two switches each, which are operated to obtain constant load power in satisfaction of calculated conduction angles. Alternatively, the switches are operated on complementary 50% duty cycles to regulate output voltage and shape the input current waveform. Output regulation is achieved by frequency control while input current wave shaping is realized by phase shifts between the two half-bridges.