文档介绍：CMOS 工艺的低压差线性
稳压器的设计
摘要
低压差线性稳压器(LDO)是电源管理集成电路当中的一种,因为它具有结构简单,低功耗,低噪声,以及封装尺寸小和较少的外围应用器件以及成本低等优点,所以它广泛应用于如手机,个人数字助理等便携式电子产品中。
低压差线性稳压器是一个典型的负反馈系统,它主要由基准电流源,基准电压预调整电路,基准电压源,过热保护电路,误差放大器,功率管和反馈电阻网络组成。基准电流源给其它模块提供偏置电流,基准电压预调整电路给基准电压源提供一个直流电压VPP,提高了基准电压源的电源抑制比,基准电压源是由带隙基准电压组成,,过热保护电路使到芯片在120OC时能够被正常关断,误差放大器使到来自基准电压源的基准电压与来自反馈电阻网络的反馈电压进行比较,并且放大其差值电压去调整功率管的栅极电压,从而改变了功率管的过驱动电压,过驱动电压的变化调整了它的输出电流,并且使到输出电压被正确的稳定到一个合适的值上。
本文采用了TSMC CMOS 工艺设计了一款低功耗,大电流,并且具有高稳定性的LDO芯片。芯片中的基准电流源采用亚阈值设计,使到它能够产生30nA的偏置电流,,也即是极大地降低了静态功耗,在设计误差放大器时,比较了传统的LDO的频率补偿方法及其缺点,提出了零点-极点跟踪频率补偿和密勒补偿,使到LDO的稳定性不依赖于负载电阻和负载电容。温度保护电路和误差放大器中的限流保护电路以及短路保护电路保证了低压差线性稳压器能够安全的工作。
本文所设计的低压差线性稳压器的设计目标为:输入电压:5V,输出电压:,最大输出电流:800mA。安全工作的温度范围:-40oC-120oC,采用TSMC CMOS工艺模型对电路进行了仿真,各项指标都满足设计要求,流片后的测试结果验证了以上的设计。
关键词:电源管理; 低压差线性稳压器;静态电流;稳定性;频率补偿;
Abstract
Low-Dropout linear voltage Regulator is a kind of power mAnagement integrated circuits. It has simple structure, low power consumption, low noise, smAll packaging and few external devices and low cost in its applications. Thus, it is widely used in such as mobile phones and personal digital assistants and other portable electronic products.
Low-Dropout linear voltage Regulator is a typical negative feedback system,it is posed of current reference source, voltage reference pre-regulator, voltage reference source, thermAl protection circuit, error amplifier, the pass transistor and feedback-work. Current reference source provide bias current, voltage reference pre-regulator provide a DC voltage VPP, enhance PSRR of voltage reference source,voltage reference source posed of Bandgap reference voltage, it provide a DC voltage . thermAl protection circuit turn-off LDO chip normAlly at 120C, The error pares the Vref created by bandgap and feedback voltage VFB, and then amplified differential signal between the Vref and VFB to adjust the gate voltage of the pass transistor to change its overdrive. The change of