【作者】 柳娟娟；

【导师】 冯全源；

【作者基本信息】 西南交通大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 近些年来，在众多的电源管理芯片中，低压差(LDO，Low-Dropout)线性稳压器由于其面积小、噪声低、静态电流小，外围器件少等优点，得到了人们越来越多的重视。它现已广泛应用于各种便携式电子产品中，特别是无线通信源管理芯片市场主要被国外公司占据，国内的发展尚处于刚刚起步阶段，因此开发具有自主知识产权的LDO线性稳压器具有很大的意义。在国家自然科学基金和四川省学术带头人基金的资助下，我们对LDO线性稳压器进行了大量研究，并重点分析和设计了其中的误差放大器和无源调整器件这两个核心模块。首先，我们对LDO线性稳压器的系统结构和工作原理进行了研究，并总结了其主要性能指标和选用原则。接着，设计了一款基于BiCMOS工艺的误差放大器。低压共源共栅电流镜负载保证放大器在低电源电压下仍具有高增益和高电源抑制比。而互补推挽结构的缓冲电路大大提高了驱动能力。采用0.5um HSPICE参数模型进行仿真，结果表明在3.6V的工作电压下，该放大器的开环增益和电源抑制比均为80dB左右，单位增益带宽高达1.2MHz，相位裕度为60°，而其建立时间还不到1μs。然后，我们对现有的一些无源调整器件的主要性能进行了总结和比较，并借助EDA工具设计了一款具有低漏电流的PMOS无源器件。最后，我们将所设计误差放大器和PMOS无源器件与LDO中的其他模块整合在一起，对整个芯片的总体性能进行了仿真，结果表明该LDO线性稳压器不仅压差电压小，而且线性调整率和负载调整率均极低。更多还原

【Abstract】 In recent years, low-dropout (LDO) linear regulator has received more and more attentions in numerous power management chips because of its small area, low noise, low supply current, few off-chip components, etc. It has been widely used in kinds of cellular electronic products, especially, wireless communication equipments, video or audio products, hand-held computers, medical apparatus, test instruments and so on. However, the market of power management chips is mainly occupied by foreign enterprises nowadays, while the development in our country is in the initial phase, so it is very meaningful to develop the LDO linear regulator with our own intellectual property.Under the support of National Science Foundation of China and Sichuan Province Academic Leaders Foundation, we have studied fully on the LDO linear regulator. Two important blocks including the error amplifier and PMOS pass element are analyzed and designed.Firstly, we have analyzed the system configuration and working principle of the LDO linear regulator. Its main characteristics and choice principle are summarized.Secondly, an error amplifier based on BiCMOS technology is designed. The low voltage cascode current mirror load ensures high gain and power supply rejection ratio under low power supply. Its driver ability is improved by the push-pull buffer stage. Simulation results employing 0.5um HSPICE model show that its open-gain and PSRR are both about 80dB under 3.6V power supply. Its bandwidth is as high as 1.2MHz and the phase margin is 60°. However, its set-up time is no more than 1μs.In addition, we have summarized and compared the primary characteristics of some existing pass elements. A PMOS pass element with low leakage current is devised under the help of EDA tools.In the end, we have integrated the error amplifier and PMOS pass element together with the other blocks of the LDO linear regulator. Then, we have simulated the main characteristics of the LDO linear regulator. The simulation results show that the LDO linear regulator not only has low dropout voltage but also ultra-low line regulation and load regulation.更多还原