All-Grounded Passive Elements Voltage-Mode DVCC-Based Universal Filters

In this paper two new voltage-mode (VM) universal filters employing three plus-type differential voltage current conveyors (DVCC+s) and grounded passive elements are presented. The first proposed filter is a single-input five-output (SIFO) circuit which can realize simultaneously all of the standard responses, i.e. low-pass (LP), band-pass (BP), high-pass (HP), all-pass (AP) and notch (NH) from the same configuration. The second proposed circuit is a three-input single-output (TISO) universal filter for realizing standard responses depending on the selection of the input signal from the same topology. Both of the proposed filters have the advantage of a high input impedance, which enables easy cascading to obtain higher order filters. The proposed filters are simulated using the SPICE program to verify the theoretical analysis.     

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.     

Voltage-Mode New Universal Biquad Filter Configuration Using a Single VDIBA

A universal voltage-mode filter configuration employing a voltage differencing inverting buffered amplifier (VDIBA), two capacitors and a resistor is proposed. The presented structure can realize all the five standard biquadratic filters: low-pass, high-pass, band-pass, band-reject and all-pass, without changing the circuit topology. The proposed filter circuit also provides the following advantageous features, not available simultaneously in any of the single active element/device based universal biquad realizing all the five filter responses known earlier so far: (i) independent electronic tuning of natural angular frequency (ω ₀) and bandwidth (BW), (ii) no requirement of any element matching condition or inversion of input signal(s) (as needed in most of the earlier reported structures), and (iii) low active and passive sensitivities. Moreover, even the internal structure of the new building block is possibly the simplest among all recently introduced new building blocks. The workability of the proposed filter has been confirmed by SPICE simulations using 0.18 μm technology.     

Voltage-mode FDCCII-based universal filters

Three new voltage-mode universal biquadratic filters configuration are proposed. The first proposed high-input impedance universal filter with single input and five outputs, which can simultaneously realize voltage-mode lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP) filter responses employing all grounded passive components. The second proposed high-input impedance universal filter with three input and single output, which also can realize all the standard filter functions without requiring any inverting input voltage signal. The third proposed universal filter with three inputs and five outputs, which can be used as either a three-input single-output or a two-input five-output universal filter. Moreover, each of the proposed circuits still enjoys (i) the employment of only grounded capacitors, and (ii) no requirement with the component choice conditions to realize specific filtering functions.     

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.     

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。     

Design of a new low power MISO multi-mode universal biquad OTA-C filter

ABSTRACT

In this article, a new low-power multiple-input, single-output (MISO) multi-mode universal biquad operational transconductance amplifier-capacitor (OTA-C) filter with a minimum number of active and passive components is proposed. The proposed filter employs three OTAs, one inverter and two grounded capacitors. The proposed filter can realise all filter frequency responses including low-pass (LP), band-pass (BP), high-pass (HP), band-stop (BS) and all-pass (AP) in all operation modes including voltage, current, tranasresistance and transconductance modes using the same topology. Furthermore, sensitivity analysis is done which shows that the proposed filter has a low sensitivity to the values of the active and passive elements. The proposed filter is simulated in HSPICE using 0.18 µm CMOS technology. The HSPICE simulation results demonstrate that the proposed filter consumes only 35 μW at 2.5 MHz from a ±0.5 V supply voltage, while all of the transistors are biased in strong inversion region. Also, the simulation results are in a close agreement with the theoretical analysis which is done in MATLAB. Furthermore, the process, voltage and temperature variation simulations are done to study the effect of non-idealities on the performance of the proposed filter. It is shown that the simulation results justify a 4.8%, 0.8% and 20% variations of the centre frequency for process, voltage and temperature, respectively. Finally, Monte-Carlo, noise and transient simulations are done to justify the good performance of the proposed filter performance.     

High input impedance voltage-mode universal biquadratic filter using two OTAs and one CCII

A three-input and single-output voltage-mode universal biquadratic filter with high input impedance, using only two operational transconductance amplifiers (OTAs), one plus-type second-generation current conveyor (CCII) and two capacitors, is presented. The proposed circuit can realize all the standard filter responses, that is, highpass, bandpass, lowpass, notch and allpass filters, from the same configuration. The proposed circuit has no requirements for component matching conditions.     

Design of a CMOS Compatible CFOA and its Application in Analog Filtering

It is presented the design of a current-feedback operational amplifier (CFOA) which is suitable for implementation with standard CMOS integratedcircuit technology of 0.35µm. The characteristics of the CFOA are derived by using biases of ±2.5V and Ibias=20µA. The usefulness of the CFOA is demonstrated by designing mixed-mode biquads which realize the low-pass, high-pass, band-pass, notch and all-pass filter functions. As a result, it is highlighted that the SPICE simulations of the biquad working in voltage-mode are in good agreement with the biquad working in current-mode.     

基于MOCCCⅡ-C的二阶多功能电流模式滤波器

提出了一种基于第二代电流控制传输器(CCCⅡ)的电流模式滤波器。电路由2个第二代多输出电流控制传输器(MOCCCⅡs)和2个接地电容构成,通过选择不同的输出端口可以实现高通、带通、低通、带阻、全通的功能。调整MOC-CCⅡs的偏置电流和电容值可以改变特征参数,产生的电路具有很低的灵敏度。最后对引入的MOCCCⅡ及提出的电路进行PSpice仿真。     

用第三代电流传送器设计n阶有源滤波器

提出了一种基于第三代电流传送器(CCIII)的电流模式n阶通用滤波器的设计方法,导出了设计公式,利用该方法可生成n阶高通、低通、带通滤波器,所产生的n阶滤波电路由n个CCIII+、2 n个无源元件构成。以二阶滤波器为例分析了高通、低通、带通滤波电路,结果显示各滤波电路的无源灵敏度和有源灵敏度都很低,以极点角频率106 ...     

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.     

基于MO-OTA-C的n阶通用电流模式滤波器

以OTA-C为基本模块,在其输入端加入一个电流信号,使输出电流受其控制,然后利用多端输出(MO)的OTA-C实现n阶通用电流模式滤波器的设计。该滤波器能实现低通、高通、带通、带阻和全通功能,n阶滤波器仅需要n个OTA和n个电容,便于集成。以三阶Butterworth滤波器为例,进行低通、带通和高通仿真。理论分析与Spice仿真表明,所设计的滤波器结构正确可行。     

On the Realization of Universal Current Mode Biquads Using a Single CFOA

The four terminal Current feedback op-amps (CFOA) with an external compensation pin, such as AD844, have received prominent attention during the past decade as alternative building blocks for analog circuit design because of their significant advantages over the traditional voltage-mode op-amp (VOA). A popular application of CFOAs has been in realizing voltage-mode (VM) and current-mode (CM) biquad filters. Previously known universal CM biquads (i.e. those capable of realizing all the five generic filter functions namely, low-pass, band-pass, high-pass, notch and all-pass) realizable with CFOAs require two to nine CFOAs. Although a few dual-function/three-function single-CFOA-based CM circuits have appeared in literature, no single-CFOA-based canonic universal CM biquad with explicit CM output has been reported in the literature up until now. This paper fills this void by presenting a set of eight minimal universal CM biquads all of which are realizable with only a single CFOA. The non-ideal analysis of the proposed circuits has been presented, their comparative features, advantages and limitations have been brought out. The workability of all the proposed circuits has been confirmed by PSPICE simulations and experimental results based upon AD844 type CFOAs.     

A power efficient continuous time ΔΣ modulator with 15 MHz bandwidth and 70 dB dynamic range

A state variable block diagram method is given for the realization of universal biquadratic transfer functions employing second-generation current-controlled conveyors (CCCIIs). Using minimum number of passive components and properly adjusting the bias currents of CCCIIs, the proposed circuits can realize all the tunable frequency standard filter functions: high-pass, band-pass, low-pass, notch-pass, and all-pass by choosing appropriate input branches without changing the passive elements. These presented circuits are in current-mode and voltage-mode separately. The non-ideality analyses of these configurations are given. Additionally, a high-order low-pass filter derived from the proposed voltage-mode biquadratic filter is introduced. PSPICE simulation results are included to verify the theory.     

A NEW MULTIFUNCTION SWITCHED-CURRENT FILTER

A new switched-current(SI)biquadratic filter is presented which can simultaneouslyprovide the low-pass,high-pass and band-pass filters in a single building block.A symbol torepresent the universal SI integrator is also introduced.It can simplify the analysis and synthesisof SI networks.     

基于MOCCCII-C的双二阶电流模式滤波器

本文提出了一种基于多输出端电流控制电流传输器(multiple outputs current controlled conveyors II)的双二阶电流模式滤波器电路,该滤波器结构简单,仅包含2个有源器件、2个接地电容.在不改变内部电路的情况下只需改变外部输入电流的接入方式和接入数目就可以实现二阶低通、高通、带通、带阻、全通滤波功能,面向实际电路完成了PSpice仿真,结果表明提出的电路正确有效.     

一种新颖的电流模式双二阶OTA-C滤波器设计

提出了一种新颖OTA-C实现的电流模式双二阶通用滤波器。该滤波器具有三个输入端和一个输出端,通过选择不同的输入信号即能实现低通、高通、带通、带阻和全通五种滤波器功能。电路结构简单、中心频率和品质因数可调,灵敏度低,均为0.5。理论分析和SPICE仿真表明所提电路方案正确可行。     

Versatile universal voltage-mode filter employing DDCCs

A new versatile universal voltage-mode biquad with three inputs and five outputs using only two differential difference current conveyors (DDCCs), two grounded capacitors, and three resistors is proposed. The proposed configuration which can be used as either a single-input five-output filter or three-input two-output filter and which can simultaneously realize all five different generic filtering lowpass, bandpass, highpass, bandstop, and allpass signals is unlike the previously reported works and still enjoys (i) the employment all grounded capacitors, (ii) no need to employ inverting-type input signals, (iii) orthogonal control of the resonance angular frequency and the quality factor, (iv) simultaneous realization of lowpass, bandpass, highpass, bandstop, and allpass responses for the single-input five-output filter, and (v) no need to impose component choice to realize all five generic responses for the three-input two-output filter.