Thde Design Of A White LED Boost Driver Chip

White LED has been hailed as one of the most promising green light source with anadvantage of high-performance and low cost. To ensure that it works stably and efficiently,favorable driver is essential. A White LEDs Boost Driver chip is designed in this thesis, whichcan be widely used in portable devices as laptop, digital camera, GPS receiver and so on.The designed circuit adopts BOOST structure and current PWM control mode. It candrive six LEDs at most with the input voltage ranging from3V to5V. The highest outputvoltage can reach to21V.The size of output current could be adjusted according to thefeedback system. It can use peripheral devices to flexibly set up the application circuit.According to the design requirements, the chip adopts a standard BJT process, to ensure thatthe layout area smaller, low design cost, efficiency can reach84%.Firstly, the development and future of the White LED drive chip, several constructions ofswitching power supply and the comparison of two kinds of PWM control model and rampcompensation are introduced in this thesis. And then, according to the design requirement, theintegrated structure is set up, typical application and matters that need attention is illustrated.Afterwards, the thesis carries out function simulation for all of the sub-circuits module and thewhole module respectively by Spectre software; they all meet the requirements of the design.Lastly, the process and layout are briefly discussed.