Design of the White LED Driving Chip with Digital Brightness Adjustment

• Main Authors: Dong-Ming Yu, 游東明
• Other Authors: 宋國明
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/68rf9f

碩士 === 國立臺北科技大學 === 電機工程系所 === 94 === This paper will describe the white LED driver with digital brightness adjustment on chip. By using the control structure of current-limited pulse frequency modulation, we can implement the Boost DC-to-DC switching converter. Furthermore, the brightness turning will be completed with the pulse width modulation technique. When the input voltage is 3V, the system output voltage can be boosted up to 23V and the output current value is greater than 40mA. Thus the output port can supply two loops of current (each one flow through 20mA), one is for the base source light of the LCD, the other for the source light of brightness adjustment. Each loop can drive six white LEDs. The proposed chip is designed and implemented with the TSMC 0.35um 2P4M CMOS process. The simulation results show that the chip area, the power efficiency, the output voltage and the output current are 1.39mm×1.53mm, 87%, 23V, 40mA, respectively.