Design Of The Control IC Applied In A White LED Driver Powered By 220VAC

White LED is expected to become a new lighting source after the conventional incandescence lamp and fluorescence lamp with its merits including high efficiency,energy conservation,environment protection,long-life time,easy to be maintained and so on. Because its electrics parameters are unstable and sensitive to the temperature,white LED needs to be drived by special control IC.A control IC which is applied in the white LED driver powered by 220V±20% is designed in this paper. There is a high voltage power transistor integrated inside. Peak value current PWM mode is adopted to deal with the current signal(secondary feedback)which is produced by the output current and voltage feedback signal to modulate PWM controller.Thereby,the functions constant current/restrained voltage and constant voltage/restrained current can be realized and then the function to drive LED can be realized too. In this paper,first,the whole frame plot of this IC was designed according to the practice application. In addition,the operation principle of this IC was analysed according to the driver circuit. Second,based on Chrt 0.35μm CMOS process,the low voltage control circuites were designed and simulated by Cadence which is a kind of EDA tools,including voltage and current references,OSC,undervoltage lockout circuit with hysteresis,overvoltage protect circuit,operational amplifier,leading-edge blanking circuit,PWM logic circuit and so on. Third,a 700V LDMOS device was designed by Medici. At the end,the realization of this control IC's process and layout were introduced,and the layout of some cells were completed according to the design rule.