Σ-Δ ADC无条件稳定理想OTA-C积分器

提出了一种基于有源自举增益提升技术的近似理想的 OTA- C积分器电路 ,详细分析了有关原理、稳定条件、失真、失配等特性 ,该积分器无条件稳定工作于Σ-Δ ADC闭环系统中。以一阶 Σ- Δ ADC为例 ,进行了模拟验证 ,该结构还具有低压应用的特点     

Transconductance improvement method for low-voltage bulk-driven input stage

A proposed transconductance enhanced method for low-voltage bulk-driven input stage is presented in this paper. The basic idea is to use current–shunt auxiliary amplifier to improve the voltage gain from the inputs to the gates of bulk-driven pairs. The enhanced voltage gain of the auxiliary amplifier leads to the improvement of the effective transconductance of the input stage. Results show that the transconductance of the OTA using the proposed bulk-driven input stage improves almost 200% without additional power and area dissipation compared to the conventional bulk-driven counterpart.     

用光纤环路镜实现WDM系统中的EDFA增益均衡

EDFA对不同波长的光产生的增益不同 ,这种增益不平坦特性成为 WDM系统中高速率、大容量信息传输的障碍 ,因此对 EDFA的增益进行均衡就显得特别重要。介绍用光纤环路镜实现 EDFA增益均衡的机理 ,并进行了实验 ,结果表明该方法简单易行 ,均衡效果显著     

差分式CMOS多功能电流模式滤波器

本文提出多端输出的CMOS电流加法器，在此基础上提出了新型差分式CMOS多功能电流模式滤波器的信号流图和电路。该滤波电路能同时产生二阶低通、带通、高通输出，并通过适当的连接能产生二阶带阻和全通滤波输出。对提出的滤波器截止频率为1MHz的电路进行了计算机PSPICE仿真。     

一种低电压的Sigma-Delta ADC新结构

介绍了一种低电压Sigma-Delta ADC新结构,该结构采用了二阶单位增益ΣΔ调制器和一阶传统ΣΔ调制器相结合的方式,既可以从系统级降低对运放直流增益等非理想因素的要求,又可以减少加法器的个数、降低电路的复杂度。在此基础上,采用HJTC0.18μm1.8V/3.3V1P6M混合信号工艺,实现了一种1V工作电压的ΣΔ调制器,经测试动态范围可以达到69.5dB。     

一种改进型有源电流镜的设计

在分析输入-输出箝位型电流镜性能的基础上，提出了一种改进型电流镜电路。通过Austria MIckro Systeme 0．61μm n 井CMOS工艺的MSIM3v3模型参数的specteS防真结果表明在5个数量级范围内．其分辨率都在10bit以上(误差小于I／2LSB)，可用于5MHz抽样速度的ADC电路中。     

一种低电压的全差分OTA

文章介绍了一种低电压的全差分OTA的实现，通过电流驱动体效应（CDB）使低电源电压OTA设计成为可能。提出了一种新的共模反馈结构（CMFB）实现了全差分输出，提高了OTA的输出范围。文章采用0．18um CMOS工艺库。SPICE仿真结果表明：在电源电压为800mV时，OTA的增益为59．2DB，单位增益带宽为14．3MHz．输出范围为674mV．     

注入光敏三极管输出特性再研究

详细报道了在洲入光敏三极管的研究工作中发现的几个较在意义的实验结果，它为研制出使用更为方便，特性更好的间接耦合光电三极管提供了很有价值的参考资料，也有助于机理问题的最终解决。     

非理想第二类电流传送器及其应用

本文定义了一种非理想第二类电流传送器(NCCII);给出了用跨导运算放大器(OTA)实现NCCII的电路;讨论了用该电路实现的电容和电阻变换器。     

Pareto ANOVA analysis for CMOS 0.18 µm two-stage Op-amp

This paper presents a Pareto ANOVA analysis technique as an alternative way to analyze some selected optimization parameters in two-stage op-amp. Three input parameters and two output parameters based on standard L₂₇(3¹³) in Taguchi method have been chosen in this optimization methodology. The input parameters are selected based on the value of W/L ratio at three transistors which are transistor M8, M9 and M7. Two types of outputs have been aimed to optimize which are power dissipation and gain. This op-amp has been constructed by using CMOS technology 0.18 µm and the results have been verified by using a Mentor Graphic EldoSpice. From the analysis, it is found that level 16 has been chosen as an optimal combination produced by a Taguchi method. After this, Pareto ANOVA technique will be applied to analyze the effect of selected input parameters in achieving optimum gain and power of the two stage op-amp. The analysis showed that the value of W/L ratio at transistor M9 gives a major impact on power dissipation and value of W/L ratio at transistors M8 and M9 give a major impact on gain. This study also shows that Pareto ANOVA is an easier method to analyze circuit parameters.     

FTTH光接收机功率放大器的设计与改进

在分析国内外FTTH光接收机应用前景和普通光接收机的功率放大器基础上,用MMIC替代通用放大模块,设计并经过优化改进找到了一款适合FTTH的CATV光接收机功率放大器.通过测试,性能指标完全符合要求,具有很好的实用价值.     

高精度电流源电路的设计

提出了一种高精度的电流源电路,通过V/I变换,将由带隙基准电压电路产生的与温度和电源电压无关的带隙基准电压转换成与温度和电压无关的高精度基准电流,并通过高精度电流镜结构产生所需的镜像电流,有效地抑制了由于温度、电源电压、负载阻抗的变化及干扰对电流源的影响.用HSPICE对改进前后的电路进行对比测试,结果表明,改进后电流镜的镜像误差约减小90%,电流源的精度显著提高.     

On the systematic synthesis of OTA-based Wien oscillators

A NAM expansion method for systematic synthesis of OTA-based Wien oscillators is given. Moreover, the NAM expansion method for four different classes of the oscillators is considered. The class I oscillators employ three OTAs, the class II oscillators employ four OTAs, the class III oscillators employ five OTAs, and the class IV oscillators employ six OTAs. Each class has 32 different forms, resulting in 128 Wien oscillators using OTAs. Having used grounded capacitors, the circuits are easy to be integrated and their parameters can be tuned electronically through tuning bias currents of the OTAs. The MULTISIM simulation results have been included to support the generation method.