Current driver targets LED strings in streetlights

摘要

Lighting fixtures that cover wide areas, such as streetlights, often use LED matrices comprising strings of HB LEDs (high-brightness light-emitting diodes) that rely on off-the-shelf constant-current, ac/ dc power supplies. Because the ac/dc power supply drives the entire matrix, complications can arise when one string fails open or begins to draw too much current. These situations can overstress the string's LEDs and create either a gap or a noticeable bright streak in the matrix. However, providing current control for each string adds too many components and increases the light's cost.