共查询到19条相似文献,搜索用时 359 毫秒
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基于0.13 μm CMOS工艺,提出并设计了一种应用于三级全差分运算放大器中的新型共模反馈电路。将具有密勒补偿结构的典型两级全差分结构和源随器结构作为三级运算放大器的放大级,通过在共模反馈电路中引入前馈通路,产生的两个零点提高运放的稳定性,解决了传统共模反馈电路中多个极点难以补偿的问题。仿真结果表明,在1.2 V电源电压下,共模下增益为70.4 dB,单位增益带宽为56 MHz,相位裕度为85.5°。相比于传统无前馈电路,新型共模反馈电路的单位增益带宽和相位裕度分别提高了8.2 MHz和17.4°。具有这种共模反馈结构的运算放大器可以实现较低的电源电压和较好的相位裕度。 相似文献
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给出了一种用在高速高精度流水线型模数转换器中的具有高增益和高单位增益频率的全差动CMOS运算放大器的设计,电路结构主要采用折叠式共源共栅结构,并采用增益提高技术提高放大器的增益。共模反馈电路由开关电容共模反馈电路实现。模拟结果显示,其开环直流增益可达到106 dB,在负载电容为2 pF时单位增益频率达到了167 MHz,满足了对模数转换器的高速度和高精度的要求。 相似文献
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两级运放中共模反馈电路的分析与设计 总被引:1,自引:0,他引:1
在两级共源共栅CMOS运算放大器中,设计了一种新的共模反馈电路。这种电路克服了一般共模反馈电路存在的限制输出摆幅的缺点,在稳定电路直流工作点的同时,能有效提高电路的输出摆幅。通过对共模电路结构的分析,证明了其功能原理的正确性。基于0.18μm(3V)CMOS工艺库,用Hspice软件对电路结构进行了仿真验证。结果显示,电路低频增益达到120dB,功耗不到0.24mW。 相似文献
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一个用于14位采样保持电路的全差分增益增强放大器的分析和设计 总被引:1,自引:0,他引:1
介绍了一种全差分增益增强CMOS运算放大器的设计和实现。该放大器用于14位20 MHz采样频率的流水线模/数转换器(A/D)的采样保持电路。为了实现大的输入共模范围,采用折叠式共源共栅放大器。主放大器采用开关电容共模反馈电路在获得大输出摆幅的同时降低了功耗。辅助放大器则采用简单的连续时间共模反馈电路。该放大器采用UMC Logic 0.25μm工艺,电源电压为2.5 V。Hspice仿真结果显示,在负载为15 pF的情况下,其增益为104 dB,单位增益带宽为166 MHz。 相似文献
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针对传统全差分运算放大器电路存在输入输出摆幅小和共模抑制比低的问题,提出了一种高共模抑制比轨到轨全差分运算放大器电路。电路的输入级采用基于电流补偿技术的互补差分输入对,实现较大的输入信号摆幅;中间级采用折叠式共源共栅结构,获得较大的增益和输出摆幅;输出级采用共模反馈环路控制的A类输出结构,同时对共模反馈环路进行密勒补偿,提高电路的共模抑制比和环路稳定性。提出的全差分运算放大器电路基于中芯国际(SMIC) 0.13μm CMOS工艺设计,结果表明,该电路在3.3 V供电电压下,负载电容为5 pF时,可实现轨到轨的输入输出信号摆幅;当输入共模电平为1.65 V时,直流增益为108.9 dB,相位裕度为77.5°,单位增益带宽为12.71 MHz;共模反馈环路增益为97.7 dB,相位裕度为71.3°;共模抑制比为237.7 dB,电源抑制比为209.6 dB,等效输入参考噪声为37.9 nV/Hz1/2@100 kHz。 相似文献
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《Electronics letters》2008,44(21):1225-1226
A new switched-capacitor (SC) common-mode feedback (CMFB) circuit for fully-differential operational amplifiers (op-amps) is presented. By reducing the amplifier capacitive load with respect to conventional SC-CMFB schemes, the proposed solution guarantees a significant improvement of the op-amp speed performance. A typical SC integrator employing the new CMFB has also been designed in 0.35 μm CMOS technology. Simulation results show that, for a given power consumption, the op-amp settling time can be about halved by using the proposed CMFB instead of the conventional one. 相似文献
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This paper presents an optimization-based design methodology for fully differential amplifiers (FDAs) including the effects of real common-mode feedback (CMFB) circuits as constraints in the design flow. The sizing procedure is performed separately for the main amplifier and for the CMFB circuit, reducing the number of free variables and exploring the design space in a more efficient way. Also, this methodology can be employed to design single and two-stages FDAs whereas a second pole compensation scheme is necessary. In order to validate the proposed methodology, a two-stage fully differential amplifier with a no capacitor feed-forward (NCFF) compensation technique was designed in 0.13 μm CMOS technology with a 1.2 V power supply. The presented results also include a pole-zero pair mismatch analysis and proposes a solution in order to compensate the generated pole-zero doublet that might affect the performance of the amplifier. We can show that this approach reduces the overall static power consumption while satisfying the design specifications. 相似文献
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Two CMOS differential amplifiers, one that is intended for applications in which the input common-mode range is relatively limited, the complementary self-biased differential amplifier (CSDA), and one that is intended for applications in which the input common-mode range is bounded only by the supply voltages, the very-wide-common-mode-range differential amplifier (VCDA), are discussed. Both differ from conventional CMOS differential amplifiers in having fully complementary configurations and in being self-biased through negative feedback. The amplifiers have been applied as precision high-speed comparators in commercial VLSI CMOS integrated circuits 相似文献
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A switched op amp with a fast common mode feedback (CMFB) circuit is presented. The proposed fully differential two stage amplifier needs CMFB only for the second stage, and thus a fast and simple passive CMFB circuit may be used. The amplifier is capable of 1 V operation and has no limitation on the maximum supply voltage 相似文献
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Apirak Suadet Varakorn Kasemsuwan 《Analog Integrated Circuits and Signal Processing》2013,74(2):387-398
This paper presents a CMOS inverter-based class-AB pseudo-differential amplifier comprising current-mode common-mode feedback (CMFB). The circuit employs two CMOS inverters and the complementary CMFB consisting of current-mode common-mode (CM) detector and transimpedance amplifier. The circuit has been designed using 0.18 μm CMOS technology and operates at 1 V supply. The simulation results demonstrate rail-to-rail operation with low CM gain (?15 dB). The power dissipation of the circuit is 102.5 μW. 相似文献
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Gupta A.K. Dhanasekaran V. Soundarapandian K. Sanchez-Sinencio E. 《Electronics letters》2006,42(9):499-500
A method for stabilising the common-mode feedback (CMFB) loop in high-speed fully differential two-stage amplifiers is presented. Existing approaches may prove to be inadequate for high-speed designs. The problem becomes acute because of positive DC feedback by external network, which leads to 'latching states'. The proposed multipath approach avoids the latching states while maintaining the stability of the CMFB loop. 相似文献
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Duque-Carrillo J.F. Ausin J.L. Torelli G. Valverde J.M. Deminguez M.A. 《Solid-State Circuits, IEEE Journal of》2000,35(1):33-44
The constraints on the design of CMOS operational amplifiers with rail-to-rail input range for extremely low supply voltage operation, are addressed. Two design approaches for amplifiers based on complementary input differential pairs and a single input pair, respectively, are presented. The first realizes a feedforward action to accommodate the common-mode (CM) component of the input signals to the amplifier input range. The second approach performs a negative feedback action over the input CM signal. Two operational amplifiers based on the proposed approaches have been designed for 1-V total supply operation, and fabricated in a standard 1.2-μm CMOS process. Experimental results are provided and the corresponding performances are discussed and compared 相似文献