采用单位增益放大器的高Q小电容分散的SC带通滤波器

本文提出了一种新的采用单位增益放大器的开关电容(SC)电路。该电路用于高Q带通滤波器实现时,可获得很小的电容分散,较同类的其它SC电路的电容分散有大幅度的减小。     

具有混合反馈的高Q和/或高f_s开关电容带通滤波器

本文提出了一种减少电容分布和总电容的高Q和/或高f_s开关电容(SC)带通滤波器。在传统的双二次SC滤波器结构中,引入部分正反馈并改变前馈网络可使总电容和电容分布得到大幅度的减少。举例说明了二阶高Q(=50)SC带通滤波器设计,并比较了不同滤波器结构的性能参数。     

一个新的高Q单放大器开关电容滤波器及其最佳设计

本文提出了一个新的高Q单放大器开关电容(SC)滤波器,给出了该电路最大与最小电容比最小的最优设计。同已有文献相比,本文电路的最大与最小电容比已得到大幅度地减小。     

开关电容滤波器的系统设计与实现

通过合理选择滤波器的类型和阶数,利用低Q值二级滤波器放在高Q值二级滤波器的前级,给每一级分配不同的增益使得每一级的输出峰值相同.从开关电容电路的原理入手,分析了开关电容电路和电容编程阵列,最终设计一个可编程开关电容6阶带通滤波器.选择合适的运算放大器参数.可编程滤波器系统共需3路时钟控制,滤波器编程参数控制模块用于实现芯片内部程序存储器编程控制.通过对设计的开关电容滤波器进行仿真,结果基本与设计目标吻合.     

减小SC滤波器中GB效应的新结构

本文讨论了在开关电容(SC)滤波器中如何减少增益带宽积(GB)效应的问题,提出了一个减少GB效应的新的双二次拓扑结构,此结构对寄生电容不敏感,并且具有很低的无源W0,Q灵敏度。以低通SC滤波器为例,给出了减小GB效应的具体设计方法。并用设计实例和实验结果证明了所得结论的正确性。     

一种适合带通/宽带滤波器的新型电流差放大器

介绍了一种具有双端电流电流输出的电流差大器的新型结构，应用这种电流差放大器，在实现处理电流的一附规范全通滤波器的基础上，导出了新型电流模式高Q值二阶带通滤波器和宽带滤波器。其中，高Q值带通滤波器不受元件匹配条件的约束，调节Q值时不影响中心频率f0。上述电路的PSPICE仿真结果与理论分析相互吻合。     

通用有源电流模式滤波器及其仿真

采用信号流图设计了由两个 OTA和一个 MOCC + / -构成的三输入一输出电流模式二阶滤波器新电路 ,合理选择输入电流可实现低通、高通、带通、带阻及全通滤波功能。所提电路结构简单 ,中心频率ω0 和品质因数 Q独立可调 ,无源元件全部接地 ,滤波器特性参数对无源元件灵敏度低。理论分析和 MOS管级的 PSPICE仿真表明所提电路方案正确     

基于OTA-C的多功能全集成电流模式双2阶滤波器

采用TSMC 0.18 μm CMOS工艺,设计了一种基于OTA的单输入多输出的多功能电流模式双2阶滤波器。滤波器的5个输出端口可同时得到低通、高通、带通、带阻和全通5种滤波功能。该电路结构简单,仅需要4个MO-OTA和2个电容;电路固有角频率ω₀及品质因数Q值独立可调;灵敏度低,均小于或等于0.5。基于BSIM3模型参数,采用Hspice仿真工具对电路进行了仿真,结果表明滤波器性能良好,版图符合设计要求。     

采用单运算跨导放大器的混合模式滤波器

提出了一种新颖的单运算跨导放大器的混合模式滤波器电路。由该电路可实现一阶低通,一阶高通,二阶低通及二阶带通滤波器,所有滤波器仅由一个ＯＴＡ及３－４个ＲＣ元件构成。分析了各种滤波器的灵敏度,并给出了实验结果。     

基于单OTA的电压模式滤波器

提出了一个基于单ＯＴＡ的电压模式滤波器模型电路,该模型电路仅由一个ＯＴＡ 及三个ＲＣ元件构成。由该电路可产生出一阶低通、一阶高通及二阶低通、二阶带通滤波器。各滤波器具有很低的灵敏度。与诸文献［１～５］的ＯＴＡ滤波器相比,结构简单且三个ＲＣ元件中有两个接地,仅一个浮端,便于集成。文中还分析了各滤波器的截止频率和通频带,给出了电路的实验结果。     

多功能开关电流双二次滤波器生成

本文提出了一个具有差分输出的通用开关电流一阶积木块，并阐述了采用该积木块生成多功能ＳＩ滤波器的系统方法，以单放大器，两放大器和三放大器有源ＲＣ或ＳＣ网络为原型，系统地导出了一系列新的ＳＩ双二次结构，生成的所有ＳＩ电路均可在单一积木块上同时获得低通、高通和带通滤波功能，这些电路的灵敏度低，且为纯ＭＯＣ管结构，非常适合于数字ＣＭＯＳ工艺集成。     

Switched-capacitor filters

A novel technique for building active filters using switched-capacitor (SC) circuits is proposed. Principles of operation, methods of control, analysis, and design of a typical SC filter are presented. To assess its effectiveness, the technique is used to control input current harmonics in a phase-controlled converter. It is shown that a wide range of harmonics can be controlled using a single filter     

CMOS switched-current ladder filters

The design and implementation of switched-current (SI) ladder filters is described. The basic current-mode circuits, including the SI differential integrator/summer are developed. The SI integrator/summer is shown to be directly analogous to the switched-capacitor (SC) integrator/summer; thus, all the synthesis techniques developed for the design of SC filters can be used to synthesize SI filters. Signal flowgraph synthesis of SI ladder filters is presented. The nonideal characteristics of SI ladder filters that limit their accuracy are evaluated. Clock-feedthrough and device mismatch induced errors are more severe in the present SI circuit configurations than in SC circuits. A standard digital 2-μm n-well CMOS process has been used to implement two high-order ladder filters. Simulations accurately predict the measured results of the first integrated SI filters. The area and power dissipation are comparable to those obtained with the switched-capacitor technique     

减小电容分布的单放大器开关电容带通滤波器

本文将正反馈引入到单放大器无限增益负反馈结构中,提出了四个新的带有部分正反馈的单放大器开关电容带通滤波器,得到了这些电路在给定极点频率ω_0和(?)值的设计方程和最小电容分布的最佳设计。同文献中的电路相比,本文电路的电容分布得到大幅度地减小。     

A new simple method for analysing of thermal noise in switched-capacitor filters

Thermal noise is one of the most important challenges in analogue integrated circuits design. This problem is more crucial in switched-capacitor (SC) filters due to the aliasing effect of wide-band thermal noise. In this article, a new simple method is proposed for estimating the power spectrum density of output thermal noise in SC filters, which have acceptable accuracy and short running time. In the proposed method, first using HSPICE simulator, accurate value of accumulated sampled noise on sampler capacitors in each clock state is achieved. Next, using difference equations of the SC filter, frequency response of the SC filter is shaped by time domain analysis. Based on the proposed method, a SC low-pass filter and a second-order SC band-pass filter are analysed. The results are validated by comparing to the previously measured data.     

基于信号流图的开关电流滤波器设计

开关电流（SI）是有望取代开关电容（SC）的一种新型的取样数据技术，鉴于SC技术发展的成熟性及其与SI技术的紧密联系，即SC和SI滤波电路具有互易性，可采用信号流图转置的方法，将SC综合法直接用于SI滤波器设计，而无须提出新的设计方法。本文以二阶巴特沃思开关电容带通滤皮器为例给出了该方法的具体应用。     

Noise-cancelling switched-capacitor (SC) filtering technique

A method of reducing the 1/f noise in SC filters is shown using an initialising technique. This technique also removes the input offset of the operational amplifier, and thus gives an offset-free SC building block. Experimental results for a first-order lowpass filter illustrating the above are presented.     

HIGH SELECTIVITY SC BANDPASS FILTERS WITH LESS CAPACITOR SPREAD

Two novel switched-capacitor(SC)bandpass filters using a single operational am-plifier(op amp)are presented.Optimal designs for minimizing capacitor spread are also given.Gain-bandwidth product(GB)effects of op amps on the proposed SC circuits are taken intoconsideration.Comparisons with the proposed circuits and the circuits given by the literatureshow that the new circuits require less chip area in monolithic integration and are less sensitiveto the GB effects.     

Implementation of switched capacitor fractional order differentiator (PDδ) circuit

This paper proposes a novel implementation of switched capacitor (SC) fractional order differentiators (FOD) based on Tustin operator and Al-Alaoui operator. The existing models of half differentiator s ^1/2 have been expanded using continued fraction expansion and implemented using PSpice. The PSpice simulation results are compared with the theoretical results in the continuous time domain. The results validate the effectiveness of the SC circuit implementation of the proposed approach. A detailed analysis of the influence of the non-idealities of the third order Al-Alaoui operator based half differentiator is performed. The analytical expressions for errors in magnitude and phase due to the above mentioned non-idealities have been derived for the SC integrator and amplifier circuits used in our realisation.