Improve Buck and Buck-Boost circuit LED driver

• Main Authors: Wei-lun Wang, 王偉倫
• Other Authors: Kuo-hsing Cheng
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/36723731737946120972

碩士 === 國立中央大學 === 電機工程研究所碩士在職專班 === 100 === Light-emitting diode (LED) always are applied in indicator lighting before. As the technique of the LED is mature, the luminous efficiency of the LED is upgraded.Therefore,the LED are applied in lighting area now. Moreover,the cost keep going down,the power-saving LED are attractive us . There are many species of LED applied in lighting area,In this thesis a cup light selected as the LED lighting source.The cup light is applied as a shop lighting.It is always used project onto commodity in cupboard.It is can highlight commodity quality and different.Prior to this is used lighting source of Halogen.However,its problems are high power consumption and short life. The application specification of the cup light LED is input voltage AC/DC 12 Volts and loading current is 350mA.The tradition control modes of the LED application are Buck and Buck-Boost modes.The Buck control mode has higher energy efficiency.But when the input voltage is under the specification,the LED current will not setting into the specification range.The Buck-Boost can stable LED current for setting range when input voltage is under.But it is lower efficiency. This thesis improves the circuit architecture of the LED control mode.It is integrate with Buck and Buck-Boost circuit.By input voltage via resistor divide and reference voltage compare,it is can control operating mode with Buck and Buck-Boost by input voltage.It is can stable LED current.