LINEAR CONSTANT-CURRENT LED DRIVE CIRCUIT FOR ELIMINATING CURRENT RIPPLE, AND LED LIGHT-EMITTING DEVICE

摘要

Disclosed are a linear constant-current LED drive circuit for eliminating a current ripple, and an LED light-emitting device. The drive circuit comprises a first branch and a second branch connected in parallel to each other, wherein the first branch comprises a ripple filtering chip (20) and an LED load (10) connected in series; the second branch comprises a first capacitor (C1); and a whole after parallel connection of the first branch and the second branch, and a linear constant-current control circuit (30) are connected in series between direct-current output ends of rectifier bridges (50). With respect to a traditional method using a means of increasing capacitance, the ripple filtering chip (20) and the LED load (10) are connected in series and then are connected to the first capacitor (C1) in parallel, and driven by such a method, the first capacitor (C1) does not need larger capacitance, so that the capacitance of the capacitor can be greatly reduced, and the purpose of eliminating a current ripple of an LED light string can be achieved, current at two ends of the LED light string is kept constant, a smaller system area is occupied as well, and the flexibility of an application of a system is increased and the stability of the system is improved.