LED Linear Solution Introduction
Nowadays, it is getting harder and harder to decrease the cost of switching LED driver because switching solution is very mature.
Against this backdrop, Linear LED driver comes up.
Comparing to switching solution, the features of linear led driver are:
l Very low cost (few component, looks clean).
l High PF.
l Able to realize driver on board application.
l No EMI issue.
But linear led driver still needs to overcome following issues:
l Need multiple steps to achieve good THD (single harmonic) performance.
l Low efficiency /Efficacy.
l Difficult to take more than 2KV surge.
l Fault condition.
How it works?
As the schematic showed (it’s a typical 4 channels driver). Led channels turned step by step as rectified voltage goes up.