The volt-ampere characteristic of high-power LED is the
main parameter that describes characteristics of LED chip PN
junction, with nonlinear that operating current (1) and theapplied voltage (U) expresses as exponential relationship.
Figure 1 is the high-power LED voltage characteristic curve,
which describes the nonlinear relationship curve of the normal
operation the forward voltage drop (U) and forward current
(I) . As is shown in Figure 1, when the LED forward voltage
exceeds a certain threshold, I will dramatically increases with
the increasing of U. Small changes of U will cause large
changes in 1.