In the specific implementation, however, adjust the forward current dimming may produce a more serious problem.
We know that the c is usually driven DC-DC constant current drive power, and such constant current drive source is usually divided into two kinds of step-up or step-down (of course, the buck, but because of low efficiency, The prices are not commonly used). LED forward voltage is determined by its forward current. We can see from the volt-ampere characteristic of the LED forward current changes will cause the corresponding changes of the forward voltage, or more precisely, the decrease of the forward current can also cause the forward voltage decreases. Therefore, to reduce the current, led high bay light forward voltage will follow reduced. This will change the relationship between supply voltage and load voltage.
For example, an input of 24V LED lamps, 8 1W high power LED series. For a boost type constant current source must work at the buck does not work, the last high lumen led flashlights will flicker. In fact, as long as the boost type constant current source, adjust the forward current dimming transferred to the low brightness almost certainly will produce flicker. Time of the LED load voltage must be lower than the supply voltage. Many people do not understand one of the problems, but also the total going to the dimming circuit to find the problem, it is futile.
Step-down constant current source of as if originally the supply voltage is higher than the load voltage when the brightness is to low-key, the load voltage is reduced, they still need to step-down constant current source.