LED Constant Current Driver Circuit Design

With the fast development of Chinese economy, the requirement for LED Displays become larger. They are widely used in many fields such as telecommunications, finance, traffic, gymnasium etc. LED drivers are necessary in the application of LED displays. They can supply constant output current and make the LED light even, and also can make the LED’s life longer. At present, there are many companies of ASIC for LED such as TOSHIBA, TI, SONY, MBI, SITI etc.In this thesis, a 16-channel-LED driver IC with constant current is designed and tape out. It is designed with 0.5um CMOS technology, input voltage ranged in 3.3V～5.5V. The output current range of each channel is 2mA～90mA and is regulable. In this design, the current match between each channel is 1% typically. It has better output current accurate than normal 8-channel-LED driver IC with constant current, more output channels and better output current regulate accurate. It has very small die size and can raise the output and reduce the cost.In this thesis, based on the analysis of principles of the multi-channel constant current LED driver chip, and under the guidance of the analysis of the specific performance, we did sub-circuit design and simulation, the overall circuit co-simulation and analysis. And describes the placement and routing, design and verification of the layout. Finally the post-layout simulation was done. Through the analysis of test data, the chip achieved better function, more in line with SPEC, and has a smaller chip area.The thesis is a production of circuit principles and simulation practice. Based on the circuit principle analysis, the sub-block circuits and the whole chip circuit are simulated by applying the EDA tool HSPICE. The simulation results indicate that the whole chip have achieved the design specification. Furthermore, the circuit principle analysis and simulation methods have been verified.