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。     

Electronically Tunable Current-Mode Universal Filter Employing Only Plus-Type Current-Controlled Conveyors and Grounded Capacitors

A new current-mode current-controlled three-input single-output universal filter, which employs only five plus-type second-generation current-controlled current conveyors (CCCIIs) and two grounded capacitors, is presented in this paper. The proposed configuration provides lowpass, bandpass, highpass, bandstop, and allpass current responses at a high impedance terminal, which enables easy cascadability of the circuit. The filter also offers independent electronic control of the natural frequency ω_o and the quality factor Q through adjusting of the bias current of the CCCII. Derived analytical expressions for the filter parameter deviations due to CCCII nonidealities are also included. PSPICE simulation results are performed to confirm the theoretical analysis.     

Tunable Ladder-Type Realization of Current-Mode Elliptic Filters

It is shown that a new series FDNR-R equivalent circuit using current controlled current conveyors (CCCIIs) allows effective realization of jω-axis zeros which are known to complicate the active implementation of ladder-type elliptic filters. The resulting ladder-type elliptic filter employs all grounded capacitors while keeping the number of active elements small. Also, the filter parameters are electronically tunable, which is important from integration point of view.     

A CMOS Digitally Programmable Universal Current-Mode Filter

A new digitally programmable universal current-mode biquad filter is proposed. The filter is based on digitally controlled current followers (DCCFs). It utilizes gains of the DCCFs to provide precise frequency and/or gain characteristics that can be digitally tuned over a wide range. All parameters of the proposed filter can be adjusted independently. Experimental results obtained from a 0.35-$mu$m standard CMOS chip are provided.      

基于CMOS MOCCCII的电调谐电流模式多功能滤波器

设计了一种基于CMOS多输出第二代电流控制传输器 (MOCCCII) 的可调谐电流模式双输入、多输出多功能滤波器.该滤波器仅由两个CCCII、一个接地电阻和两个接地电容组成.选择输出端中的一个或它们的组合,即可实现低通、带通、高通、带阻和全通5种二阶滤波功能.电路结构简单,且固有频率ωo和品质因数Q可独立调节;具有较低的有源和无源灵敏度.HSPICE仿真结果表明,设计的电路是正确的.     

基于MO-CDTA的电控调谐多功能电流模式二阶滤波器/振荡器

描述了一个基于多输出电流差分跨导放大器(MO-CDTA)的多功能电流模式二阶电路.该电路仅使用四个MO-CDTA和两个接地电容,能同时和分别实现高通、带通和低通电流传输函数,电路的极点频率和品质因素能独立地被电控调节;电路也能被修饰成一个电流控制的正弦振荡器.计算机仿真表明电路正确有效.     

电流模式N阶CDBA-RC通用滤波器的系统设计

该文提出了利用电流差分缓冲放大器CDBA(the Current Differencing Buffered Amplifier)实现n阶电流模式滤波器的方法。基于信号流图给出了系统的设计公式,并举例设计了5阶Butterworth低通、高通及4阶Butterworth带通滤波器。PSPICE仿真表明,结果与理论分析完全吻合。该滤波器不仅电路结构简单,而且用的元件数目很少。     

Voltage/Current-Mode Universal Filter Using FTFN and CFA

A novel configuration for realizing voltage/current-mode (VM/CM) universal filter using a single four terminal floating nullor (FTFN), a single current feedback amplifier (CFA), two capacitors and three resistors is presented. The VM configuration has three inputs and a single output and implements all the five generic filtering functions through the selection of inputs. This topology enjoys cascadability and does not require any additional active element for facilitating the filter realizations. The same circuit in current-mode has a single input and four outputs and realizes LP, HP and two BP responses simultaneously from which AP and Notch can also be realized. This topology uses grounded resistors and capacitors which are ideal for monolithic integration. Both the topologies enjoy orthogonal control of natural frequency (ω₀) and quality factor (Q) by the grounded resistors. The topologies enjoy low active and passive sensitivity figures. Experimental and PSPICE simulation results are also included.     

Single FDCCII-Based Tunable Universal Voltage-Mode Filter

None of the previously reported voltage-mode universal biquad filters with three inputs and a single output offers either of the following two important advantages: (i) the use of only one active element and (ii) independent control of ω₀ and ω₀/Q. In this paper, a novel biquad filter, achieving both of these advantages, is presented. HSPICE simulation results using TSMC025 process and ±1.25 V supply voltages validate the theoretical predictions.     

一种具有最少元件双二阶滤波器的OTA实现电路

提出了一种新的双二阶滤波器的OTA实现电路。该结构具有最少的元件，滤波器特性参数均可独立调节等特点。给出了二阶滤波器设计实例并经计算机仿真所验证。     

Universal Current-Mode Active-C Filter Employing Minimum Number of Passive Elements

A universal current-mode active-C filter simultaneously realizing low-pass, band-pass and high-pass responses is proposed. The filter can also realize notch and all-pass responses with interconnection of relevant output currents. The presented filter employs four second-generation current controlled conveyors (CCCIIs) as active elements and only two capacitors as passive elements. The proposed active-C filter can be tuned electronically, and has low element sensitivities.     

用AOA Deboo积分器设计通用二阶电流模滤波器

为了获得高精度的通用二阶电流模滤波器,根据伴随网络的概念,以基于VFA电压模Deboo积分器为原型,先给出了AOA电流模Deboo积分器,再给出AOA电流模多路输出比例电路,最后设计出了极点频率为31.8kHz,品质因素为1,通带增益为4的通用二阶电流模滤波器.该电路的参数取决于电阻比,两积分电容接地,因而适合VLSI单片集成技术.计算机仿真与理论分析一致.     

Tunable mixed-mode OTA-C universal filter

A novel electronically tunable mixed-mode universal biquad by using four single-output and one dual-output-operational transconductance amplifiers, two grounded capacitors is proposed. The proposed circuit has ability to realize voltage, current, transconductance, and transresistance mode, and can the following advantageous features: (i) realization of low-pass, band-pass, high-pass, notch, and all-pass filter responses from the same configuration, (ii) employment of only grounded capacitors ideal for integrated circuit implementation, (iii) orthogonal controlling of ω _o and Q for easily electronic tunability, and (iv) low active and passive sensitivity performance. Finally, to verify our architecture, we have designed this analog filter chip with TSMC 0.35-μm 2P4M CMOS technology. This chip operates to 1 MHz and consumes 30.95 mW. The chip area of the analog filter is about 0.823 mm².     

On the Realization of Current－Mode Continuous－Time Operational Transconductance Capacitance Filter

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Multiple-Mode OTA-C Universal Biquad Filters

Two new multiple-mode (including voltage, current, transconductance, and transresistance modes) OTA-C universal biquad filters are proposed. The first proposed circuit uses only four operational transconductance amplifiers (OTAs) and two grounded capacitors. The second proposed circuit uses five OTAs and two grounded capacitors. Both the proposed circuits can realize voltage, current, transconductance, and transresistance mode universal filtering responses (low-pass, high-pass, band-pass, notch, and all-pass) from the same topology. The first proposed circuit uses the least number of components. This represents an attractive feature from a chip area and power consumption point of view. The second proposed circuit has no need of extra inverting and non-inverting amplifiers for special input signals. Moreover, both the proposed biquads still have (i) the employment of two grounded capacitors, (ii) cascadable connection of the former voltage-mode stage and the latter current-mode stage, and (iii) low sensitivity performance. H-SPICE simulation results confirm the theoretical analysis.     

截止频率精确可调跨导电容滤波器实现

提出了一种新的利用开关电容技术调节偏置电流值大小的电路,应用该电路可以精确调节跨导运放Gm值的大小。采用既具有电压共模负反馈(CMFB)电路, 又同时具有工作在线性区的MOS管作源极反馈有源电阻, 实现其良好线性度的跨导运放。设计了三阶椭圆函数低通滤波器,并实现其频率的精确可调。应用台积电(TSMC)2层多晶硅,4层金属(2P4M),3.3V电源电压,0.35m CMOS工艺Spice model仿真得到的频响曲线与理想情况十分接近。     

用AOA广义阻抗变换器设计高阶电流模式滤波器

为了获得高精度、高稳定性和低灵敏度的高阶电流模式滤波器,根据伴随网络的概念,以传统的基于电压反馈运算放大器(VFA)的广义阻抗变换器(GIC)为原型,先设计出基于伴随运算放大器(AOA)的电流模式接地GIC,并讨论了由GIC所组成的频变负阻、电容-电阻变换.再利用L.T.Bruton变换,将经典梯形LC五阶Butterworth低通滤波器转换为梯形五阶有源电流模式低通滤波器.计算机仿真与理论分析一致.     

一种用CFA实现的通用高阶滤波器

以信号流图为基础,用CFA设计了一种通用高阶滤波电路。这种电路结构由CFA和电阻、电容组成,具有通用性,只需调整接地阻抗的值,就能实现高阶低通、带通、高通及带阻几种不同的滤波功能。列举了四阶带通和五阶高通两种滤波器,并对两种滤波器进行了仿真,PSpice仿真结果与理论分析一致。     

单MDDCC多功能电流模式二阶滤波器的实现

提出一种单MDDCC三输入、单输出多功能电流模式二阶滤波器结构电路。该电路仅由单个DDCC有源器件及5个RC无源元件构成,能产生二阶高通、低通及带通滤波器。电路具有结构简单,灵敏度低,滤波器固有频率ω0和品质因数Q相互独立可调,便于集成。最后对所提出的滤波器进行了HSpice仿真,理论分析和计算机仿真表明电路方案正确有效。