Automotive lighting, LED light source inside and outside of the building, as well as laptop computers or TV LCD screen backlight. The development of high-power led studio lighting technology to improve the design stage of the heat dissipation requirements. Like all other semiconductor, LED is not overheating, so as not to accelerate the weakening of output, or result in the worst situation: a total failure. Compared with incandescent lamps, high power LED with higher efficiency, but a considerable part of the input power is still turned into heat instead of light. Thus, the reliable operation of the need for good heat dissipation, and requirements in the design phase to consider the high temperature environment. Design led studio lighting driver circuit size, but also must take into account the temperature factor: must select the forward current to ensure that even if the ambient temperature reaches a maximum value, the LED chip will not overheat. With increasing temperature, by reducing the maximum allowable current, that is derated to achieve cooling.
The temperature dependence of the power supply to run led studio lighting disadvantages: the high temperature region, the LED is out of specification to run. In addition, when in the low temperature region, the lighting source powered by the significantly lower than the current maximum allowable current (see Figure 1 red curve). The green curve shown in Figure 1 (referred to as PTC thermistor) to control the led high bay lighting current through the LED driver circuit in the positive temperature coefficient thermistor is a major improvement.