Research And Design Of A LED Power Driver Chip

In recent years,the development of white LED in lighting area is growing very rapidly.Compared to traditional incandescent lighting,LED has many advantages,including lower power consumption,longer lifetime,and smaller size.Due to the extensive use of LED lighting system,LED lighting driver IC as a crucial part has also been rapidly developed.Strong guidance of the government and LED green advantages have made LED a new generation mainstream in lighting area.LED industry market competition makes the research and development of low cost LED with simple structure lighting system necessary and feasible.Firstly,it introduces the LED light-emitting principle,as well as switching power supply knowledge,including topology,control mode,operating mode and feedback methods.Then a new type of LED constant current circuit is proposed which is improved basing on the tranditional BUCK type converter.For the new system architecture,the paper analyzes the key technology to realize the new system architecture,system protection features and how to achieve excellent system parameters.This thesis has reported an LED driver IC design based on CSMC 0.8um₇.5V₃0V₇00V_BCD technology platform.According to the system-level architecture,internal function modules and protection circuit modules are defined,designed and simulated,besides,the system parameters are also simulated,and they all have reached good indicators.Finally,the overall layout is proposed,and passes the LVS and DRC verification.The chip is a high-precision tripod LED constant current driver based on BUCK converter structure.It multiplexes the CS pin which detects current peak and GND pin,and eliminates the need for start-up resistor of VCC power supply and the auxiliary winding.Peripheral topology has a simple structure and low cost.Chip supports AC85²65V input with good line regulation and load regulation,while the efficiency achieves above 85%.Power supply path is from DRAIN terminal with high voltage to VCC teminal.The chip also includes VCC under-voltage protection,output open-circuit protection and over-temperature protection regulation and such features ensure that the entire system is safe and reliable.