Design heat dissipation of high-power LED street lights

LED street light is an optoelectronic device. During its working process, only 20% to 30% of the electrical energy is converted into light energy, and the rest of the electrical energy is almost converted into heat energy, which increases the temperature of the LED. In high power LEDs, heat dissipation is a big problem. For example, if the photoelectric conversion efficiency of a 10W white LED is 20%, 8W of electrical energy will be converted into heat energy. If no heat dissipation measures are added, the core temperature of the high-power LED will rise rapidly. When the junction temperature (TJ) When the rise exceeds the maximum allowable temperature (usually 150 ℃), the high-power LED will be damaged due to overheating. Therefore, in the design of high-power LED lamps, the most important design work is the heat dissipation design. In addition, in the heat dissipation calculation of general power devices (such as power ICs), as long as the junction temperature is less than the maximum allowable junction temperature (usually 125°C), it is enough. However, in the heat dissipation design of high-power LEDs, the junction temperature TJ is required to be much lower than 125°C. The reason is that TJ has a great influence on the light extraction rate and life of the LED: the higher the TJ, the lower the light extraction rate and the shorter the life of the LED. The main heat dissipation path of high-power LED is: die → heat dissipation pad → printed board copper layer → printed board → ambient air. If the junction temperature of the LED is TJ, the temperature of the ambient air is TA, and the temperature at the bottom of the heat dissipation pad is Tc (TJ>Tc>TA), in the process of heat conduction, the thermal conductivity of various materials is different, that is, there are different thermal resistance. If the thermal resistance from the die to the bottom surface of the heat dissipation pad is RJC (the thermal resistance of the LED), the thermal resistance from the heat dissipation pad to the copper layer of the PCB surface layer is RCB, and the thermal resistance from the PCB to the ambient air is RBA, then from the tube The relationship between the total thermal resistance RJA from the junction temperature TJ of the core to the air TA and each thermal resistance is: RJAu003dRJC+RCB+RBA The unit of each thermal resistance is °C/W. It can be understood in this way: the smaller the thermal resistance, the better the thermal conductivity, that is, the better the heat dissipation performance. CHZ Changhui Lighting Technology Co., Ltd. is the leader of street lamps in East China and a leading enterprise in the solar street lamp industry. The company is committed to providing customers with new lighting solutions and high-quality services. Years of experience in Ru0026D and manufacturing of solar street lights, with a number of national technology patents such as street lights, solar street lights, garden lights, LED street lights, lighting products; the company has strong technical force, advanced production equipment, scientific and standardized management, high-quality 's workforce. The products produced by the company are complete in variety, reasonable in design, novel in style and unique in shape, and undertake various indoor and outdoor lighting projects. Company: Shanghai CHZ Changhui Lighting Technology Co., Ltd. Website: www.chz-lighting.com