Circuits and methods for driving a load with power factor correction function

摘要

A circuit for driving a load includes a power line, converter circuitry, and a controller. The power line is operable for providing an input current and an input voltage. The converter circuitry coupled to the power line is operable for converting the input voltage to a regulated voltage to drive the load, and for providing a current detection signal indicating whether a converter current flowing through the converter circuitry drops to a predetermined level. The controller coupled to the converter circuitry is operable for correcting a power factor of the circuit based on the current detection signal and the input voltage such that a waveform of the input current follows a waveform of the input voltage.