LED is called the fourth generation of light source with
high efficiency, energy saving, environmental protection, long
life and so on, which has been more widely used. Because
high-power LED is with nonlinear volt-ampere characteristics
and easily affected by temperature, needs to be driven by
constant current. The performance of LED constant-current
driver circuit relates to the total efficiency and reliability of
the lamp. Therefore, the design of constant current driver
circuit and the efficiency improving of driver circuit are two
key issues for high-power LED application design.