高PSRR超低噪声的LDO设计  

Design of LDO with high PSRR and ultra-low noise

作　　者：王甲柱 唐威 姚和平 WANG Jiazhu;TANG Wei;YAO Heping(School of Electronic Engineering,Xi’an University of Posts and Telecommunications,Xi’an 710121,P.R.China;Shanghai Engineering Research Center of Electronic Circuit Intelligent Protection,Shanghai 201202,P.R.China;Wayon Electronics Co.Ltd.,Shanghai 201202,P.R.China)

机构地区：[1]西安邮电大学电子工程学院,西安710121 [2]上海电子线路智能保护工程技术研究中心,上海201202 [3]上海维安电子有限公司,上海201202

出　　处：《重庆邮电大学学报（自然科学版）》2022年第6期1079-1087,共9页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

摘　　要：便携式医疗电子设备在信号传输中易受到噪声干扰,为了抑制交流纹波对微小信号的影响,设计了一种高电源抑制比(power supply rejection ratio,PSRR)、超低噪声的低压差线性稳压器(low-dropout regulator,LDO)。利用电流缓冲和动态零极点追踪补偿技术来实现环路的稳定,同时也扩展了环路的单位增益带宽,提高了高频下的PSRR。稳压器采用两级结构,通过预稳压调制级加低通滤波器结构来实现低压差线性稳压器的超低噪声,且低通滤波器的截止频率有利于低频下PSRR的提高。基于5 V-0.35μm CMOS工艺设计,采用cadence仿真软件进行仿真验证。仿真结果表明,在100 kHz、10 kHz、1 kHz、100 Hz频率下,PSRR分别可达到-66、-85、-96和-97 dB。在不同的负载下,输出噪声在10 Hz~100 kHz频段不超过10μVrms,重载(250 mA)时的输出噪声最低可达到7.5μVrms,可用于便携式医疗电子设备。Portable medical electronic equipment is susceptible to noise interference in signal transmission.In order to suppress the influence of AC ripple on small signals,we designed a low-dropout linear regulator(LDO)with high power supply rejection ratio(PSRR)and ultra-low noise.The current buffer and dynamic zero-pole tracking compensation technology were used to achieve the loop stability.At the same time,the unity gain bandwidth of loop was also expanded,and the PSRR at high frequencies was improved.A two-stage structure composed of a pre-regulated modulation stage and a low-pass filter was adopted to reduce the noise of the regulator to ultra-low value.In addition,the cut-off frequency of the low-pass filter was conducive to the improvement of PSRR at low frequencies.The circuit was fabricated with a 5 V-0.35μm CMOS technology.Cadence simulation software was used for simulation verification and the results show that PSRR reaches-60,-65,-85 and-90 dB at frequencies of 100 kHz,10 kHz,1 kHz,and 100 Hz,respectively.In the frequency range from 10 Hz to 100 kHz,the output noise is no more than 10μVrms under different loads.Especially under heavy load of 250 mA,the output noise can reach as low as 7.5μVrms.It can be used in portable medical electronic equipment.

关 键 词：超低噪声 高电源抑制比(PSRR) 电流缓冲 动态零极点追踪补偿 单位增益带宽 

分 类 号：TN433[电子电信—微电子学与固体电子学]