CONSTANT CURRENT LED LIGHTING CIRCUIT WITH HIGH POWER FACTOR

摘要

Disclosed is a constant current LED lighting circuit with a high power factor, which comprises a rectifier circuit (1), an LED light source load (2), and a constant current source circuit (3). The constant current LED lighting circuit with a high power factor does not have any filter capacitor. An alternating current is changed into a pulsating direct current after having been rectified by the rectifier circuit (1). The pulsating direct current forms a loop via the LED light source load (2) and the constant current source circuit (3). The constant current source circuit (3) stabilizes the voltage and current of the LED light source load (2). The LED light source load (2) comprises at least one group of LEDs in series connection. The constant current source circuit (3) comprises at least one group of constant current source devices, with each group thereof comprising at least one depletion type field effect transistor, the drain of the depletion type field effect transistor being a connection point, and the source and the gate of the depletion type field effect transistor being short-circuited with each other to form the other connection point. The present solution has the advantages of having a simple structure, few components and a long LED service life, so it can be widely used in the field of LED lighting circuits.