LED 驅動電路設計及應用

• Main Authors: YU JUI LUNG, 余瑞龍
• Other Authors: In-Hang Chung
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/67388545025945909135

碩士 === 中華大學 === 電機工程學系碩士班 === 98 === Nowadays, there are more and more emphasis on the issues of green energy because of the energy crisis and greenhouse effect in our world. For these issues, the equipment of lighting is the one that are most closely related to our human life. For the purpose of saving the usage of energy as well as reducing the emitting of carbon dioxide, based on the advantages of low power and high performance of lighting, the device of LED lighting is preferred. On the other hand, the energetic source from solar cell is considered to be a more clean and green way. Therefore, the combination of LED lighting and solar cell is indeed the best way for the equipment of lighting. However, there are existing two important problems in the apparatus of LED lighting, which is used solar cell as the energetic source. Firstly, the generation of heat will decrease the efficiency of LED lighting during the operation. The huge amounts of heat will make to drop of the forward voltage of LED, which will induce the rising current in the LED device at the constant voltage. As a result, the efficiency of LED is decreased. In addition, the matching problem between the voltage of LED and battery of solar cell will cause energy loss when energy transfers from battery to LED lighting. In this paper, we use SEPIC (Single-ended Primary Industry Converter) circuit to improve the matching problem between the voltage of LED and battery of solar cell. Besides, in order to maintain the current in LED to be constant, the method of current feedback signal control is implemented.