Design Of A High Efficiency LED Driver On Current-mode Boost DC-DC Converter

As the energy crisis,the ecological environment problems are becoming more and more serious,people need to find more environmentally friendly energy and improve energy utilization.Lighting light source as a large part of the use of energy,solving low energy conversion efficiency of the traditional light source can greatly alleviate the energy crisis.Light-emitting diode(LED)is by virtue of its low power consumption,high brightness,long life,and other advantages gradually replaced the traditional light source to become a new generation of lighting source.LED is essentially a diode structure,LED luminous brightness controlled by constant current drive.Excellent LED driver chip can greatly improve energy conversion efficiency and reduce energy consumption.This thesis first introduces the development background and significance of LED,and then analyzes the different LED driver technology.The switching power supply driver chip is selected as the LED drive design in this thesis.The following a detailed analysis of the LED light principle and step-up DC-DC converter principle,and the choice of current-mode PWM modulation method control mode to control the power switch.According to the architecture of the system,the circuit of each module is designed,including the bandgap reference voltage module,the error amplifier module,the current sampling circuit module,the slope compensation circuit module,the current limiting protection circuit module,the PWM comparator module,the oscillator circuit module,temperature protection circuit module and drive circuit module.Analyzed each module circuit design principle and the circuit is simulated,the simulation results meet the design requirements.Finally after the chip system simulation,completed the layout design and verification of the chip.The input voltage range of the constant current driver chip is 0.9V~3.3V,the output current can be controlled.The chip can drive 1W~3W white LED.The chip has over-voltage and under-voltage protection,current limiting protection,over-temperature protection and other protection.The chip realized by CSMC 0.35?m process.