大功率白光LED路灯发光板设计与驱动技术

The Designing and Driving Technology of the Illumination Board of the High Power Bright White LED Street Lamp

为最大可能提高大功率LED路灯发光板的电光转化率与散热效率,在不影响外量子效率前提下对LED芯片设计采用扩大LED芯片面积,以及电极优化技术增加LED芯片的出光量,使芯片表面热流均匀分布,芯片工作更稳定。分析了大功率白光LED的封装过程对提高芯片取光率、保障白光质量、器件散热技术的综合应用。综合上述技术及有限元分析软件对大功率LED器件封装的热阻分析结果,确定了COB(chip on board)LED芯片的阵列组装技术,为制造LED路灯发光板的最佳技术方案。LED芯片结温很容易控制在120℃以下,与外部散热技术兼容性好。通过光线最佳归一化数学模型计算了LED芯片阵列芯片间最佳距离。最后通过对各种白光LED驱动方案的比较,确定了白光LED最佳驱动方案为恒电流驱动脉宽调制(PWM)调节亮度。

For doing the best to improve the ratio of the transformation from electronic power to luminous energy and efficiency of heat dissipation for the luminous board of the high power bright white LED street lamp, the method to extend area of LED chip was adopted and don＇t decrease LED＇s external quantum efficiency when LED chip was designed and made. The technology of optimizing was adopted for increasing luminous quantity, and let LED chip＇s heat distribute on the LED chip＇s surface averagely and make LED chip work in stable status. The integrated technology was analyzed to enhance efficiency of geting light and assure the quality of white bright emission by LED device and heat dissipation of LED device. The best technology, which was adopted to array matrix of LED chips of luminous board with high on board） technology, and according to the technology power bright white LED for street lamp, is COB （ chip result, the thermal resistance of the packaging solution for high power bright white LED chip was analyzed by Finite Element Analysis Software. The technology of COB makes LED device＇s temperature easyly to be controlled below 120 ℃ when it is electrified, and it is easier for COB to compatible with external cooling devices. The optimum distance of the LED chips of the luminous board with high power bright white LED for street lamp was figured out by the formula to make bright to be best normalized. The best optimum driving scheme for high power white bright LED street lamp was defined, that LED street lamp must be drived by constant current and the brightness of the street lamp was regulated by the PWM technology at last.