Research Of White LED Drive Circuit

White LED lighting system has many characteristic, for example low power consumption, low power supply, long usage life, energy conservation, environmental protection, and so on. Because of these excellences, research of White LED Drive Circuit has crucial significance of theory and value of application. This paper work on designing a chip using technology of charge pumps which can match LTC3201. This White LED Driver can have low power consumption, low power supply, significantly better LED-to-LED bias matching, and so on. It cans adequately display potential and predominance of White LED lighting system.The paper first analyzes some main cell of White LED Drive Circuit, it is the base of designing entire circuit. Paper analyzes the mechanism of zero temperature coefficient reference, and modifies the classical configuration to deduce the circuit which can be used in practice. Paper also brings in the idea of charge pump. Discuss the two classical use modes. And analyzes the principle of DAC, paper analyze the difference variety of DAC, and then choice the parallel current mode.Paper gives main characteristic of White LED Drive Circuit. For example constant work frequence, 3-bit current control mode, MSOP10-Pin package. Analyze function of pins, then analyze the principle of operation, for example how digital signal control the output voltage, the connection between voltage of FB and control loop. And give the requirement of parameter .Design the cell of chip, this part design include band gap, charge pump, DAC, short-circuit and over temperature protected.Then design entire cuicuit adding some control net which make logical cell may control the chip. At the end, paper gives the simulation data and curve.After the IC had designed, paper designs the layout of this circuit. The chip is produced by standard CMOS 0.6μm process. The result of test shows that it achieves the aim of parameter requirement. At the same time we also found some disaccord between simulation and test result. Using the measure of test and simulation, we found the reason of these problem, and gives some advice for amend the circuit. Use compensation technology of resistors which have different temperature coefficient to solve the problem of temperature property, and use VBE reference technology to solve the stability problem of oscillator.