The Boost Voltage Adjustable Type Of White Led Driver Circuit Simulation And Design

With the rapid development of electronic technology and network communication,portable electronics products are widely used in our daily life. Along With this trend, thepower management chips, which have the character of high efficiency, low cost andhigh level of integration, became the main research area of semiconductor devices andintegrated circuit design. This paper introduces a design of white LED drive powermanagement chips. The range of input voltage is2.7-4V, output voltage achieve4.5Vcross-flow output or4.5-5.4V adjustable output through the different voltage level ofthe SEL port. The maximum load current is200mA. Drive chip adopted Boost DC-DCtopology structure and the circuit used the peak current control circuit model of PWMscheme. The internal oscillator frequency is2.5MHz. The circuit adopted rapidrecovery schottky diodes and the forward voltage drop is0.2V, so that reduced thepower consumption of the circuit. At the same time, for the reliability of the systemrequirements, the circuit also included the protected circuit of the thermal protection,over current protection, overload protection, undervoltage locking etc., which couldprotect chips to work normally without the influence of the environment.This paper demonstrated the application prospect and present situation of switchpower supply and also illustrated the feasibility of issue. After that, the paperdemonstrated the basic topological application and work principle of powermanagement chips. Then the paper introduced the whole work principle, the structureand the application circuit of Boost white LED drive chip. This paper mainlydemonstrated each module circuit of the internal Boost DC-DC circuit, including abandgap voltage source, the benchmark oscillator, sawtooth wave generator, currentsampling module and the error amp, and other important circuit. The circuit is designedby using EDA tools Orcad capture and at the same time, Hspice is used to simulate thedesigned circuit, which could determine whether the design parameters of variousmodule circuits are the same with the expected design requirements or not. Finally, thewhole circuit is simulated and the results of simulation illustrated that the Boost whiteLED drive chip had good performance, which achieve the expected performance. This chip used the chip process of1μ40V BCD, the simulation results indicatedthat the efficiency of the whole circuit reached85%and load regulation rate is0.5%/A(load current from0to100mA). Peak current was limited to900mA. All of theseresults verified the design theory and structure in this paper. This issue was a valuablestudy and try of the combination of practice and theory.