Low flicker LED driving circuit with high power factor

摘要

An LED-based lighting apparatus comprises a rectified AC voltage source having a rectified output connected to a storage capacitor through a switching device, a plurality of LED segments controlled by a linear driving circuit and at least one charging path connected between the LED segments and the storage capacitor. One or more controllable linear LED driving units may be connected in parallel with the storage capacitor to provide balance between reducing flicker and increasing power factor of the lighting apparatus.

主权项

1. An LED-based lighting apparatus, comprising:
a rectified AC voltage source having a rectified output; a switching device having a negative node connected directly to said rectified output; a storage capacitor having a positive end connected directly to a positive node of said switching device and a negative end connected directly to ground; a plurality of LED segments connected in series, each of said plurality of LED segments having one or more LEDs connected in series, and a leading LED of a leading segment of said plurality of LED segments having a positive node connected directly to said rectified output; a linear driving circuit controlling said plurality of LED segments; at least one charging path connecting either a positive node or a negative node of one of the LEDs in said plurality of LED segments to said positive end of said storage capacitor; and a controller controlling said at least one charging path; wherein said storage capacitor, said switching device and said plurality of LED segments form a discharging path for said storage capacitor to provide an LED current through said switching device to said plurality of LED segments.