This paper presents an off-line integrated full ballast to supply a 35W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (...This paper presents an off-line integrated full ballast to supply a 35W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (a buck converter) into a single switch power stage, operating with peak current control. As it will be shown, this control scheme maintains the current through the load constant, regardless of the instantaneous value of the DC link voltage. This issue allows the use of a small capacitor for the DC link, which enhances the overall system reliability. The complete ballast has full dimming capability, and all the analysis and design steps are presented, thus ensuring the fulfilling of the existing regulations. The novelty of the final solution comes from the simplicity and robustness of the control scheme in an integrated compact single-switch power stage. A final prototype of the ballast has been built and tested, and experimental results are shown in the last part of the paper. Finally, conclusions and future developments are shown.展开更多
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...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。展开更多
文摘This paper presents an off-line integrated full ballast to supply a 35W assembly of Power LEDs. The proposed solution integrates an input PFC stage (a flyback converter operating in DCM) and a DC-DC output converter (a buck converter) into a single switch power stage, operating with peak current control. As it will be shown, this control scheme maintains the current through the load constant, regardless of the instantaneous value of the DC link voltage. This issue allows the use of a small capacitor for the DC link, which enhances the overall system reliability. The complete ballast has full dimming capability, and all the analysis and design steps are presented, thus ensuring the fulfilling of the existing regulations. The novelty of the final solution comes from the simplicity and robustness of the control scheme in an integrated compact single-switch power stage. A final prototype of the ballast has been built and tested, and experimental results are shown in the last part of the paper. Finally, conclusions and future developments are shown.
文摘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。
