Constant Voltage White Led Driving Circuit

White LED has been regarded as the next generation of light source because of its power saving, high efficiency, long life, low pollution and low radioactivity. With the maturating of white LED technology, it will be applied in many regions. So a special driver IC is needed for the white LED to maintain its common working status. We have designed two different types white LED drivers. The first one is a LDO driver aiming at the field of backlight application and the second is a boost inductor DC-DC converter aiming at the application of common light source.White LED driver belongs to the power management system. Stability is the most important thing for the design of LDO. In conventional case, it relied on a off-chip ESR to maintain the LDO's stability, but this method has many flaws. In this design, we've built two different kinds of compensation schemes which decrease the LDO's dependence on the off-chip ESR.Boost inductor DC-DC converter is a kind of power switch. In this design, we build a linear model for the boost inductor DC-DC converter and simulate this model in HSPICE. Based on the system simulation results, we've realized these specifications in circuit level. This DC-DC converter adopts the most prevalent technology at present, such as current mode feedback, PWM modulation and synchronous rectification. Comparing to the conventional technology, they dramatically promote the performance of the DC-DC converter.The simulation results of these three different chips achieve to the specifications. However, constrained by the schedule, we have taped out them all but only finished the test of the LDOs. Simulation, Layout and tape out are all based on CSMC 0.6um 2P2M process.