Research And Design Of A Wide Input Range High Power LED Driver Circuit

High power LED have the advantage of the high light effect and high current except the common LED characteristics of energy saving, long lifespan, environmental protection and high reliability. It makes"Green Lighting"apply to street lamp, fitment lighting and car lamp more wider. The increase of the LED power have higher requirement for the drive current of the driver chip and the stability of the output current.A type of wide input range high power LED driver chip was designed in this thesis. It has input voltage from 8V to 30V, and 1A maximal output current.It can dirver high power LED above 10 in a single line.It operating frequency could be modulated on the chip, and maximal frequency is 1.35MHz. Furthermore, the chip has soft-start circuit, dimming circuit and six types safeguard functions.The first, this thesis elaborated the lighting characters of high power LED and abroad current research situation, and analysed theory of many kinds of DC-DC converters, and researched three kinds of modulation and current feedback mode and voltage feedback mode. The second, the whole chip's structure was constructed. This chip focuses on voltage feedback mode and constant output current control of Boost structure. Later, this thesis analyzes in particular main subcircuits, such as bandgap circuit, LDO regulation circuit, soft-start circuit that make use of DA control mode, dimming circuit and osc circuit and operating frequency regulation circuit. What's more, the simulation results were showed after every subcircuit. The last, this thesis shows and analyses the simulation results and the layout design of the whole chip system.The whole chip system was simulated in spectre. When input voltage was 8V, output maximal current was 1A, and output voltage was 38.6V. The result of the system simulation results shows chip could work normally and accord with design require. The layout passed DRC and LVS validation.