一种低功耗高性能AB类运算放大器的设计  

Design of a low power and high performance class AB operational amplifiers

作　　者：郑慧臻 王科平 谢生 ZHENG Huizhen;WANG Keping;XIE Sheng(School of Microelectronic,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学微电子学院,天津300072

出　　处：《哈尔滨工业大学学报》2023年第11期142-150,共9页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(61774035);江苏省自然科学基金(BK20191260)。

摘　　要：为了解决传统运算放大器在物联网系统等低功耗应用中转换速率较低和增益带宽积较小的问题,设计了一种新型的AB类运算放大器。提出了基于差分对管的电流复用技术,将输入晶体管产生的差分电流再次利用,提高了电路的输出电流,获得了更高的转换速率、增益带宽积和直流增益。此外,结合了基于自适应偏置电路的AB类输入级和局部共模反馈电路,使得运算放大器输出级的动态电流摆脱了静态电流的限制,以较小的静态电流获得了较大的动态电流,进一步提升了电路的关键性能参数。基于180 nm CMOS工艺,对运算放大器进行设计和验证。仿真结果表明:在70 pF的负载电容下,正负转换速率分别为23.55 V/μs和-31.47 V/μs,增益带宽积为2.38 MHz,直流增益为63 dB,静态功耗仅为23μW。与传统的AB类运算放大器相比,所提出的电路在实现低功耗的同时具有更高的转换速率、增益带宽积和直流增益,适用于模数转换器和电源管理等低功耗电路系统。A new class AB operational amplifier was proposed to solve the problems of low slew rate and low gain-bandwidth product of traditional operational amplifiers for low power applications such as the Internet of Things.The current reuse technology based on differential pair transistors was proposed,which reuses the differential current generated by the input transistors.As a result,the output current of the circuit is enhanced,and the slew rate,gain-bandwidth product and DC gain are improved significantly.Moreover,differential input stages with class-AB operation and local common-mode feedback circuit are combined.As a result,the dynamic current of the output stage of the operational amplifier will not be restricted by the static current,and the larger dynamic current can be obtained under the smaller static current.The operational amplifiers is designed with a 180 nm CMOS process.For a 70 pF load capacitance,the simulation results show that the positive and negative slew rates are 23.55 V/μs and-31.47 V/μs,respectively,the gain-bandwidth product is 2.38 MHz,the DC gain is 63 dB,and the static power consumption is only 23μW.The results show that,compared with the traditional class AB operational amplifier,the proposed circuit achieves higher slew rate,higher gain-bandwidth product and higher DC gain under lower power consumption.The proposed circuit is suitable for low power circuits and systems such as analog-to-digital converter and power management.

关 键 词：AB类运算放大器 电流复用技术 自适应偏置电路 局部共模反馈 高转换速率 高带宽 低功耗 

分 类 号：TN432[电子电信—微电子学与固体电子学]