| Semiconductor lighting is gradually replacing incandescent and fluorescent lighting due to its unique attributes such as high efficiency, low energy consumption, low pollution, long life and high reliability. LED technology changes with each new day, and the relative techniques of LED driver have been widely investigated.According to the different application of LED lighting, this paper finished the systematic research on a LED TRIAC dimming driver and a200W multi-output LED driver.Taking most families’ need of dimming system as well as LED’s application to dimming conditions into consideration, the triac dimming method is adopted based on the analysis and comparison of the existing dimming scheme. In the first place of the paper, some analysis were illustrated in detail, including the principle of triac dimming, as well as the dimming decoding circuit which is applied to LED lighting. In the second place, the valley fill circuit was fully introduced. At last, the paper proposed the design of a constant current Buck converter.To develop the need of LED application to street lighting, the cascaded three-stage configuration was chosen after the pre-analysis and comparison. Firstly, after the introduction of different power factor correction, the Boost PFC circuit working in boundary conduction mode was chosen, and the derivation of circuit parameter was carried out. Then after the introduction of the traditional soft switching technique as well as its advantages and disadvantages, the LLC resonant converter, which has two both the advantages, was chosen as the experiment scheme. Then it was modeled and analyzed by using fundamental sinusoidal approximation, as well as the design of resonant tank component. Finally, the BUCK topology was adopted as the experiment method of the last stage。Based on theoretical analysis, two LED drivers were designed and analyzed to finish different goals. The results of the experiment also prove the rationality and validity of this project’s design. |
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