Like all semiconductors, the LED lighting chips maximum allowable junction temperature must not exceed, so as not to cause premature aging or complete failure. If the junction temperature is kept below the critical value, then the outside temperature rises, the maximum allowable forward current must be decreased. However, if the use of radiators, can increase the forward current in the specific temperature of the outside world. LED light output with the chip junction temperature rise and decline. The above situation occurs mainly in the red and yellow LED, white LED with a smaller temperature dependence. Light efficiency and the forward current to keep pace with growth, however, the LED lighting chips installed in the junction layer and the environment with high thermal resistivity can be reduced and even reversed this effect, it is because with the rise of the junction temperature, the emission will be reduced .
In addition, when the junction temperature rises and the LED forward voltage and temperature to keep pace with growth, the dominant wavelength of the emitted light to +0.1 nm / K typical rate of growth. A variety of white LED driver circuit features competitions in 1996, Nichia, Nakamura’s found a blue LED, white led chips used in led high bay arensidered the most development potential components of the illumination source, therefore, the white LED performance improvement and commercialization of application, it instantly became the focus of national research. The white LED used in the field of trail lights, automotive lighting, traffic signals, portable electronic products, LCD monitors and other public places. White LED lighting chips with rich primary colors color temperature and high luminous efficiency characteristics.