A novel method to characterize CMOS process fluctuations in subthreshold current mirrors （SCM） is reported. The proposed model is succinct in methodology and calculation complexity compared with previous statistical...A novel method to characterize CMOS process fluctuations in subthreshold current mirrors （SCM） is reported. The proposed model is succinct in methodology and calculation complexity compared with previous statistical models. However,it provides favorable estimations of CMOS process fluctuations on the SCM circuit, which makes it promising for engineering applications. The model statistically abstracts physical parameters, which depend on the IC process, into random variables with certain mean values and standard deviations, while aggregating all the random impacts into a discrete martingale. The correctness of the proposed method is experimentally verified on an SCM circuit implemented in an SMIC 0.18μm CMOS 1P6M mixed signal process with a conversion factor of 100 in an input range from 100pA to lμA. The pro- posed theory successfully predicts - 10% of die-to-die fluctuation measured in the experiment, and also suggests the -lmV of threshold voltage standard deviation over a single die,which meets the process parameters suggested by the design kit from the foundry. The deviations between calculated probabilities and measured data are less than 8%. Meanwhile, pertinent suggestions concerning high fluctuation tolerance subthreshold analog circuit design are also made and discussed.展开更多
A novel CMOS atto-ampere current mirror （AACM） is proposed which reaches the minimum yet reported current range of 0.4 aA. Operation of this circuit is based on the source voltage modulation instead of the conventio...A novel CMOS atto-ampere current mirror （AACM） is proposed which reaches the minimum yet reported current range of 0.4 aA. Operation of this circuit is based on the source voltage modulation instead of the conventionally used gate voltage modulation which interestingly prevents usage of commonly required voltage shifting in those circuits. The proposed circuit has a simple structure prohibiting large chip area consumption which consumes extremely low power of 1.5 μW. It is thus the best choice for ultra low power low voltage （ULPLV） applications. By using a very simple frequency compensation technique, its bandwidth is widened to 15.8 kHz. Simulation results in SMIC （Semiconductor Manufacturing International Corporation） 0.18 μm CMOS technology with Hspice are presented to demonstrate the validation of the proposed current mirror.展开更多
A novel low power and low voltage current mirror with a very low current copy error is presented and the principle of its operation is discussed. In this circuit, the gain boosting regulated cascode scheme is used to ...A novel low power and low voltage current mirror with a very low current copy error is presented and the principle of its operation is discussed. In this circuit, the gain boosting regulated cascode scheme is used to improve the output resistance, while using inverter as an amplifier. The simulation results with HSPICE in TSMC 0.18 μm CMOS technology are given, which verify the high performance of the proposed structure. Simulation results show an input resistance of 0.014 Ω and an output resistance of 3 GΩ. The current copy error is favorable as low as 0.002% together with an input （the minimum input voltage of Vin,min- 0.24 V） and an output （the minimum output voltage of Vout,min~ 0.16 V） compliances while working with the 1 V power supply and the 50 μA input current. The current copy error is near zero at the input current of 27 μA. It consumes only 76μW and introduces a very low output offset current of 50 pA.展开更多
This paper presents two schemes of high performance CMOS current mirror, one of them is used for operational tran-sconductance amplifier (OTA) in analog VLSI systems. The linearity, output impedance, bandwidth and acc...This paper presents two schemes of high performance CMOS current mirror, one of them is used for operational tran-sconductance amplifier (OTA) in analog VLSI systems. The linearity, output impedance, bandwidth and accuracy are the most parameters to determine the performance of the current mirror. Here a comparison of two architectures based on same architecture of the amplifier is presented. This comparison includes: linearity, output impedance, bandwidth and accuracy. These two circuits are validated with simulation in technology AMS 0.35 μm. An operational amplifier based on the adapted current mirror is proposed. Its frequency analysis with large bandwidth is validated with the same technology.展开更多
A novel topology of current mirror （CM） with tunable output current is proposed. Two methods for output current tuning are presented. The first one utilizes an analog input voltage for linear current output, and the...A novel topology of current mirror （CM） with tunable output current is proposed. Two methods for output current tuning are presented. The first one utilizes an analog input voltage for linear current output, and the second one has an N-bit digital input signal for 2N un-continuous current outputs. A linearization method for low noise amplifier （LNA） is proposed and realized with this tunable CM. As the provider of the bias current, the CM has brought the LNA a lower NF （noise figure） and a higher IIP3 （input-referred third-order intercept point） compared with a conventional one. The experimental results show that the LNA achieves 1.47 dB NF and ＋ 19.83 dBm IIP3 at 860 MHz.展开更多
In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,p...In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,parallel-connected independent-excitation direct-current(DC)motors for mud pumps,that are supplied by a single power converter.This configuration results in electrical power imbalance,thus reducing its efficiency.This paper investigates this power imbalance issue in such legacy DC mud pump drive systems and offers an innovative solution in the form of a closed-loop control system for electrical load balancing.The paper first analyzes the drilling fluid circulation and electrical drive layout to develop an analytical model that can be used for electrical load balancing and related energy efficiency improvements.Based on this analysis,a feedback control system(so-called“current mirror”control system)is designed to balance the electrical load(i.e.,armature currents)of parallel-connected DC machines by adjusting the excitation current of one of the DC machines,thus mitigating the power imbalance of the electrical drive.Theproposed control systemeffectiveness has been validated,first through simulations,followed by experimental testing on a deep drilling rig during commissioning and field tests.The results demonstrate the practical viability of the proposed“current mirror”control system that can effectively and rather quickly equalize the armature currents of both DC machines in a parallel-connected electrical drive,and thus balance both the electrical and mechanical load of individual DC machines under realistic operating conditions of the mud pump electrical drive.展开更多
A new Dark Current Suppression (DCS) CMOS readout circuits for large format Quantum-Well-Infrared Photo-detector (QWIP) Focal-Plane-Array (FPA) with novel Correlated-Double-Sampling (CDS) structure based on dynamic so...A new Dark Current Suppression (DCS) CMOS readout circuits for large format Quantum-Well-Infrared Photo-detector (QWIP) Focal-Plane-Array (FPA) with novel Correlated-Double-Sampling (CDS) structure based on dynamic source-follower are proposed, which can overcome the drawbacks of the present techniques, such as sensitive to the non-uniformity of the QWIP materials, poor readout noise features, low frame frequency, limited injection efficiency and dynamic range, etc. The dummy is adopted to realize dark current suppression, while the cascode current mirror (with current ratio of 1:10) can increase charge sensitivity and reduce integration time. Through the novel CDS structure, the output waveform is boxcar, and the frame frequency is increased. Simulation results demonstrate that, in high background sense, the proposed DCS circuit can suppress the dark current, achieve good readout performance, such as low power consumption, high charge sensitivity, high resolution, large dynamic range, and insensitive to the non-uniformity of the QWIP materials.展开更多
电流镜输出误差主要由3个不同失配源造成:漏源电压(V_(DS)),阈值电压(V_(th)),跨导系数(β)。其中,第一项V_(DS)失配通常是由有限输出阻抗引起的确定性误差,该误差可以通过使用级联结构以及增益提升技术避免,后两项V_(th)和β失配是由...电流镜输出误差主要由3个不同失配源造成:漏源电压(V_(DS)),阈值电压(V_(th)),跨导系数(β)。其中,第一项V_(DS)失配通常是由有限输出阻抗引起的确定性误差,该误差可以通过使用级联结构以及增益提升技术避免,后两项V_(th)和β失配是由工艺引起的随机性误差。为解决电流镜因工艺失配现象导致的电压电流(Voltage to Current)转换电路精度、线性度较差的问题,提出了一种动态元件匹配(Dynamic Element Match,DEM)以及修调技术(TRIM)相结合的电流镜校准方法,该方法使用TRIM技术将待校准输出电流镜支路和基准电流镜支路之间的误差电流,通过电容与MOS管转换成校准电流后反馈流入待校准输出电流镜支路完成校准,并通过DEM技术切换多条待校准输出电流镜支路完成校准的同时使输出误差平均化。本文采用SMIC 0.18μm BCD工艺对所提出的V-I转换电路进行了电路设计,仿真结果表明,V-I转换电路的输出电流的失配误差从0.12%下降到了0.03%,有效位数ENOB达到了11.2 bit,总谐波失真THD为−72.6 dB。展开更多
Abstract In the four-anode device, the mirror magnetic field affects the characteristics of charged particles motion, so that the current-voltage relations of glow discharge are changed. Firstly, the discharge device ...Abstract In the four-anode device, the mirror magnetic field affects the characteristics of charged particles motion, so that the current-voltage relations of glow discharge are changed. Firstly, the discharge device is introduced, and the distribution of mirror magnetic field generated by the loops surrounding the discharge chamber is presented. Both the discharge current-voltage characteristics and the radial distributions of electron density are measured, respectively, with/without the magnetic field. When the discharge occurs in a 99.99% helium with a pressure ranging from 100 Pa to 800 Pa without magnetic field, the voltage, sustaining a certain abnormal glow discharge current, decreases with the increase in gas pressure. With a mirror magnetic field of certain intensity, the discharge voltage increases with the current in a rate slower than that without the magnetic field. Moreover, when the magnetic field intensity increases, the discharge voltage first decreases then increases. Simultaneously, the mirror magnetic field affects the moving characteristics of charged particles, and causes a more inhomogeneous electron density.展开更多
目的系统评价经颅直流电刺激(tDCS)联合镜像疗法(MT)对脑卒中患者上肢功能和日常生活活动能力的康复效果。方法计算机检索PubMed、Web of Science、The Cochrane library、Embase、中国知网、万方、维普和中国生物医学文献数据库,收集...目的系统评价经颅直流电刺激(tDCS)联合镜像疗法(MT)对脑卒中患者上肢功能和日常生活活动能力的康复效果。方法计算机检索PubMed、Web of Science、The Cochrane library、Embase、中国知网、万方、维普和中国生物医学文献数据库,收集所有经tDCS联合MT治疗脑卒中患者上肢障碍的随机对照试验,检索时限从建库至2023年1月,由两名研究者独立提取数据。使用RevMan5.4软件进行Meta分析。评价主要结局指标:Fugl-Meyer上肢功能评定量表(FMA-UL)评分和改良Barthel指数量表(MBI)评分。次要结局指标:盒子积木测试(BBT)评分。结果共纳入7篇随机对照试验,包含379例患者。Meta分析结果显示,与单独tDCS组相比,联合组FMA-UL评分[MD=5.17,95%CI(3.80,6.54)]和MBI评分[MD=6.71,95%CI(4.61,8.80)]均显著提高;与单独MT组相比,联合组FMA-UL评分[MD=6.72,95%CI(3.67,9.76)]、MBI评分[MD=17.91,95%CI(2.49,33.33)]及BBT评分[MD=9.52,95%CI(3.30,15.74)]均显著提高。结论相较于单独使用tDCS或MT,tDCS联合MT改善脑卒中患者上肢运动功能和日常生活活动能力的疗效更显著。展开更多
文摘A novel method to characterize CMOS process fluctuations in subthreshold current mirrors （SCM） is reported. The proposed model is succinct in methodology and calculation complexity compared with previous statistical models. However,it provides favorable estimations of CMOS process fluctuations on the SCM circuit, which makes it promising for engineering applications. The model statistically abstracts physical parameters, which depend on the IC process, into random variables with certain mean values and standard deviations, while aggregating all the random impacts into a discrete martingale. The correctness of the proposed method is experimentally verified on an SCM circuit implemented in an SMIC 0.18μm CMOS 1P6M mixed signal process with a conversion factor of 100 in an input range from 100pA to lμA. The pro- posed theory successfully predicts - 10% of die-to-die fluctuation measured in the experiment, and also suggests the -lmV of threshold voltage standard deviation over a single die,which meets the process parameters suggested by the design kit from the foundry. The deviations between calculated probabilities and measured data are less than 8%. Meanwhile, pertinent suggestions concerning high fluctuation tolerance subthreshold analog circuit design are also made and discussed.
文摘A novel CMOS atto-ampere current mirror （AACM） is proposed which reaches the minimum yet reported current range of 0.4 aA. Operation of this circuit is based on the source voltage modulation instead of the conventionally used gate voltage modulation which interestingly prevents usage of commonly required voltage shifting in those circuits. The proposed circuit has a simple structure prohibiting large chip area consumption which consumes extremely low power of 1.5 μW. It is thus the best choice for ultra low power low voltage （ULPLV） applications. By using a very simple frequency compensation technique, its bandwidth is widened to 15.8 kHz. Simulation results in SMIC （Semiconductor Manufacturing International Corporation） 0.18 μm CMOS technology with Hspice are presented to demonstrate the validation of the proposed current mirror.
基金supported by the Iran University of Science and Technology
文摘A novel low power and low voltage current mirror with a very low current copy error is presented and the principle of its operation is discussed. In this circuit, the gain boosting regulated cascode scheme is used to improve the output resistance, while using inverter as an amplifier. The simulation results with HSPICE in TSMC 0.18 μm CMOS technology are given, which verify the high performance of the proposed structure. Simulation results show an input resistance of 0.014 Ω and an output resistance of 3 GΩ. The current copy error is favorable as low as 0.002% together with an input （the minimum input voltage of Vin,min- 0.24 V） and an output （the minimum output voltage of Vout,min~ 0.16 V） compliances while working with the 1 V power supply and the 50 μA input current. The current copy error is near zero at the input current of 27 μA. It consumes only 76μW and introduces a very low output offset current of 50 pA.
文摘This paper presents two schemes of high performance CMOS current mirror, one of them is used for operational tran-sconductance amplifier (OTA) in analog VLSI systems. The linearity, output impedance, bandwidth and accuracy are the most parameters to determine the performance of the current mirror. Here a comparison of two architectures based on same architecture of the amplifier is presented. This comparison includes: linearity, output impedance, bandwidth and accuracy. These two circuits are validated with simulation in technology AMS 0.35 μm. An operational amplifier based on the adapted current mirror is proposed. Its frequency analysis with large bandwidth is validated with the same technology.
基金supported by the Tianjin Natural Science Foundation,China(No.09JCYBJC00700)
文摘A novel topology of current mirror （CM） with tunable output current is proposed. Two methods for output current tuning are presented. The first one utilizes an analog input voltage for linear current output, and the second one has an N-bit digital input signal for 2N un-continuous current outputs. A linearization method for low noise amplifier （LNA） is proposed and realized with this tunable CM. As the provider of the bias current, the CM has brought the LNA a lower NF （noise figure） and a higher IIP3 （input-referred third-order intercept point） compared with a conventional one. The experimental results show that the LNA achieves 1.47 dB NF and ＋ 19.83 dBm IIP3 at 860 MHz.
文摘In deep drilling applications,such as those for geothermal energy,there are many challenges,such as those related to efficient operation of the drilling fluid(mud)pumping system.Legacy drilling rigs often use paired,parallel-connected independent-excitation direct-current(DC)motors for mud pumps,that are supplied by a single power converter.This configuration results in electrical power imbalance,thus reducing its efficiency.This paper investigates this power imbalance issue in such legacy DC mud pump drive systems and offers an innovative solution in the form of a closed-loop control system for electrical load balancing.The paper first analyzes the drilling fluid circulation and electrical drive layout to develop an analytical model that can be used for electrical load balancing and related energy efficiency improvements.Based on this analysis,a feedback control system(so-called“current mirror”control system)is designed to balance the electrical load(i.e.,armature currents)of parallel-connected DC machines by adjusting the excitation current of one of the DC machines,thus mitigating the power imbalance of the electrical drive.Theproposed control systemeffectiveness has been validated,first through simulations,followed by experimental testing on a deep drilling rig during commissioning and field tests.The results demonstrate the practical viability of the proposed“current mirror”control system that can effectively and rather quickly equalize the armature currents of both DC machines in a parallel-connected electrical drive,and thus balance both the electrical and mechanical load of individual DC machines under realistic operating conditions of the mud pump electrical drive.
基金Supported by the National Natural Science Foundation of China(No.60077025)
文摘A new Dark Current Suppression (DCS) CMOS readout circuits for large format Quantum-Well-Infrared Photo-detector (QWIP) Focal-Plane-Array (FPA) with novel Correlated-Double-Sampling (CDS) structure based on dynamic source-follower are proposed, which can overcome the drawbacks of the present techniques, such as sensitive to the non-uniformity of the QWIP materials, poor readout noise features, low frame frequency, limited injection efficiency and dynamic range, etc. The dummy is adopted to realize dark current suppression, while the cascode current mirror (with current ratio of 1:10) can increase charge sensitivity and reduce integration time. Through the novel CDS structure, the output waveform is boxcar, and the frame frequency is increased. Simulation results demonstrate that, in high background sense, the proposed DCS circuit can suppress the dark current, achieve good readout performance, such as low power consumption, high charge sensitivity, high resolution, large dynamic range, and insensitive to the non-uniformity of the QWIP materials.
文摘电流镜输出误差主要由3个不同失配源造成:漏源电压(V_(DS)),阈值电压(V_(th)),跨导系数(β)。其中,第一项V_(DS)失配通常是由有限输出阻抗引起的确定性误差,该误差可以通过使用级联结构以及增益提升技术避免,后两项V_(th)和β失配是由工艺引起的随机性误差。为解决电流镜因工艺失配现象导致的电压电流(Voltage to Current)转换电路精度、线性度较差的问题,提出了一种动态元件匹配(Dynamic Element Match,DEM)以及修调技术(TRIM)相结合的电流镜校准方法,该方法使用TRIM技术将待校准输出电流镜支路和基准电流镜支路之间的误差电流,通过电容与MOS管转换成校准电流后反馈流入待校准输出电流镜支路完成校准,并通过DEM技术切换多条待校准输出电流镜支路完成校准的同时使输出误差平均化。本文采用SMIC 0.18μm BCD工艺对所提出的V-I转换电路进行了电路设计,仿真结果表明,V-I转换电路的输出电流的失配误差从0.12%下降到了0.03%,有效位数ENOB达到了11.2 bit,总谐波失真THD为−72.6 dB。
基金Program for New Century Excellent Talents in University (NCET) of ChinaFundation of the Key Lab of Infrared and Low Temperature Plasma of Anhui Province of China(No.2007A003003U)
文摘Abstract In the four-anode device, the mirror magnetic field affects the characteristics of charged particles motion, so that the current-voltage relations of glow discharge are changed. Firstly, the discharge device is introduced, and the distribution of mirror magnetic field generated by the loops surrounding the discharge chamber is presented. Both the discharge current-voltage characteristics and the radial distributions of electron density are measured, respectively, with/without the magnetic field. When the discharge occurs in a 99.99% helium with a pressure ranging from 100 Pa to 800 Pa without magnetic field, the voltage, sustaining a certain abnormal glow discharge current, decreases with the increase in gas pressure. With a mirror magnetic field of certain intensity, the discharge voltage increases with the current in a rate slower than that without the magnetic field. Moreover, when the magnetic field intensity increases, the discharge voltage first decreases then increases. Simultaneously, the mirror magnetic field affects the moving characteristics of charged particles, and causes a more inhomogeneous electron density.
文摘目的系统评价经颅直流电刺激(tDCS)联合镜像疗法(MT)对脑卒中患者上肢功能和日常生活活动能力的康复效果。方法计算机检索PubMed、Web of Science、The Cochrane library、Embase、中国知网、万方、维普和中国生物医学文献数据库,收集所有经tDCS联合MT治疗脑卒中患者上肢障碍的随机对照试验,检索时限从建库至2023年1月,由两名研究者独立提取数据。使用RevMan5.4软件进行Meta分析。评价主要结局指标:Fugl-Meyer上肢功能评定量表(FMA-UL)评分和改良Barthel指数量表(MBI)评分。次要结局指标:盒子积木测试(BBT)评分。结果共纳入7篇随机对照试验,包含379例患者。Meta分析结果显示,与单独tDCS组相比,联合组FMA-UL评分[MD=5.17,95%CI(3.80,6.54)]和MBI评分[MD=6.71,95%CI(4.61,8.80)]均显著提高;与单独MT组相比,联合组FMA-UL评分[MD=6.72,95%CI(3.67,9.76)]、MBI评分[MD=17.91,95%CI(2.49,33.33)]及BBT评分[MD=9.52,95%CI(3.30,15.74)]均显著提高。结论相较于单独使用tDCS或MT,tDCS联合MT改善脑卒中患者上肢运动功能和日常生活活动能力的疗效更显著。
