Abstract摘要

穩(wěn)定的全差分算法（FD）兩級放大器提出了在圖2（c）具有快速、保證無閂鎖、低偏移的同時(shí)提供一些在功耗增加簡單的跟蹤補(bǔ)償。電源電壓范圍從0.7到1.2 V的地方不斷增加的需求對模擬電源預(yù)算空間高效利用亞微米工藝。共模（CM）偏移（VOSCM），差分偏移（VOS），和noiseerode動(dòng)態(tài)范圍。共模（CM）偏移是一個(gè)經(jīng)常被忽略的誤差貢獻(xiàn)共模反饋放大器。一厘米的放大器的優(yōu)良品質(zhì)：快速解決，無鎖定操作下的瞬態(tài)條件下，，低功耗，低貢獻(xiàn)低噪音，VOSCM FD的電路，即流水線ADC。眾所周知，電流反饋可以快速，只有經(jīng)由過程[1,2]的電流增益帶寬的限制。該共模電流放大器在圖2（c）避免了閉鎖狀態(tài)的同時(shí)保持共模反饋（CMFB）環(huán)路穩(wěn)定性和簡化共模反饋補(bǔ)償。
共模偏置；差分偏移；雙級放大器；共模放大器
—A robustmethod for stabilizing fully differential (FD) two stage amplifiers is presented inFig.2(c) which is fast, guaranteed latch free, low offset while offering simpler tracking of compensation with some increase in power dissipation. Submicron processes with supply voltages ranging from 0.7 to 1.2 V place an ever increasing demand on efficient use of analog supply budget headroom. Common mode (CM) offset (VOSCM), differential offset (Vos), andnoiseerode dynamic range.  Common mode (CM) offset is an often overlooked error contributionof the CM feedback amplifier. The desirable qualities of a CM amplifier are: fast settling, latch up free operation under all transient conditions while being low power,contributing lownoise, low VOSCM to FD circuits, i.e. pipelined ADCs. It is widely known that current feedback can be fast,limited only by the current gain bandwidth of the process[1,2]. The proposed CM current amplifier in Fig. 2(c) avoids latching states while maintainingcommon mode feedback (CMFB) loop stability and simplifying CMFB compensation.

Index terms—Common mode offset; Differential offset; two stage amplifiers; Common mode amplifier

I. INTRODUCTION介紹

Fully differential two stage amplifiers are widely used as a result of increased dynamic range, attenuation of CM noise, reduced harmonic distortion, and increased bandwidth[2,3]. The major disadvantage of two stage fully differential circuits is; their potential for latch up, the need for a fast CMFB circuit to set the CM output voltage, the added noise and the VOSCM contribution to system design considerations. The CMFB amp senses the output CM voltage from the FD amplifier and using negative feedback sets the CM voltage of the differential amplifier output to a CM reference voltage, VREFCM. In this Letter, we investigatewide bandCM amplifiersfor the highlydesirable two stage amplifierinFig. 1,which haspotential positive feedback and latch up[4,5].Existing solutions reported as latch up free[4,6],can add a degree of difficultyin compensationand/or in achieving necessary desired CM amplifier bandwidth while maintain low VOSCM. Problems arises from the observation that both CM gain and FD gain share the identical 1st and 2nd stages and compensationbut with different transconductances (FD differential and CM pair) with an added CM gain stage. This difficulty is exacerbated when FD amplifier bandwidth approaches a processes unity current gain bandwidth (fTA). The proposed CMFB current amplifier (CMCA) addressesthese difficulties using current feedback (M1CM) across the bandwidth of interest with the FD amplifier in context.

II. CM LATCH UP, STABILITY AND OFFSET

III. CM TOPOLOGY COMPARISON

References文獻(xiàn)

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Guanglei An received the B.S. degree in communication engineering from Jilin University in 2004 and M.S. degree inn electronics engineering from Chongqing University of Posts and Telecommunications in 2007. He is currently working toward his Ph.D degree at Oklahoma State University in the MSVLSI design group. His research interests include low power analog and mixed-signal VLSI for biomedical applications.


Chris Hutchens (S‘71-M’73) received the B.S. and M.S. degrees in electrical engineering from South Dakota State University. He received the Ph.D. degree from the University of Missouri, in 1979. In 1986 he joined the faculty of the School of Electrical and Computer Engineering at the Oklahoma State University. His current research interests include: high temperature mixed signal VLSI, device modeling, subthreshold mixed signal CMOS for biomedical instrumentation and RFIDs, and acoustic transducer design. Dr. Hutchens is an experienced mixed signal analog designer. He has multiples years’ experience in mixed signal electronics for extreme temperature and medical markets and is a Certified Clinical Engineer. He has served as a member of the Board of Clinical Engineering Certification.






Robert L. Rennaker II received the B.S, M.S. and Ph.D. degrees in biomedical engineering from Arizona State University (1997, 2001, 2002).  In 2002 he joined the faculty of the School of Aerospace and Mechanical Engineering at The University of Oklahoma.  In 2010 he joined the faculty of the Erik Jonnson School of Engineering and Behavioral and Brain Sciences at The University of Texas at Dallas.  His current research includes the development of neural interfaces, systems level neuroscience, neural plasticity and immune response to implanted materials.
 

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