Design Of Low Dropout Voltage Linear Buck Regulator And Modeling Of Related Device

With the coming of the information era, the power management technology is becoming more and more important. The realization of power management with high efficiency and good reliability will greatly influence the performance of the system.Low dropout voltage linear buck regulator(LDO) is a power management IC mainly for portable applications. This paper firstly designed a LDO based on CMOS fabrication technology in which excellent load regulation performance and ultra-low quiescent current were achieved with the priorities of very small voltage drop between input and output and wonderful linear regulation performance. And the power supply rejection ratio of this LDO is also high. This LDO also has over-temperature protection and short-circuit protection circuits with merits of high precision, fast response and good reliability. The protection circuits can guarantee the safty of the whole circuit under destructive environment or sudden short-circuit condition. With simple outer devices, the LDO can provide a flexible, efficient and reliable power supply for different electronic products.Double Diffused Drain MOSFET (DDDMOS) is a popular power device in power management circuits and driver circuits with simple structure, CMOS compatible fabrication technology and wonderful performance. Based on the LDO's design, characteristics of Drift Drain MOSFET were simulated and analysed with the device simulation software MEDICI and a body current model was obtained, which is helpful to deeply understand reliability physics of the device and also an aid to model the breakdown voltage and device's lifetime.