基于OTA的多功能电压模滤波器及其仿真

本文采用信号流图法设计了一种基于ＯＴＡ的三输入一输出多功能电压模滤波器新电路，该电路由五个ＯＴＡ和两个接地电容构成，合理选择输入电压可实现低通、高通、带通、带阻及全通滤波功能。文章还对电路进行了ＭＯＳ管级的计算机仿真，其结果表明所提出的电路方案正确有效。     

CCII-based PID controllers employing grounded passive components

In this paper, both of current-mode and voltage-mode proportional plus integral plus derivative (PID) controllers employing the second-generation current conveyors (CCIIs) as active elements are developed. The presented novel PID controllers have grounded passive elements that do not need passive element matching, and realize independently adjustable PID parameters. Thus, it is easy to implement these PID controllers in integrated circuits. Several computer simulations are presented to demonstrate the behavior of these proposed PID controllers.     

Electronically tunable voltage-mode universal filter with single-input five-output using simple OTAs

This article presents a new electronically tunable voltage-mode universal biquadratic filter with single-input five-output using simple operational transconductance amplifiers (OTAs) and grounded capacitors. The proposed configuration provides low-pass, band-pass, high-pass, band-stop and all-pass voltage responses at a high-impedance input terminal that enables easy cascading in voltage-mode. The natural frequency and the quality factor can be set orthogonally by adjusting the circuit components. The natural frequency can also be controlled electronically by adjusting the bias currents of the OTAs. For realising all the five standard filtering functions, no critical-matching conditions are imposed and all the incremental parameter sensitivities are low. Experimental and simulation results that confirm the theoretical predictions are given.     

New voltage-mode universal filter and sinusoidal oscillator using only single DBTA

In this article, a new voltage-mode second-order universal frequency filter and sinusoidal oscillator using only single differential-input buffered and transconductance amplifier (DBTA) is presented. The proposed voltage-mode filter structure using single DBTA and four passive elements can provide all standard filter functions, i.e. low-, band-, high-pass, band-stop, and all-pass without changing the circuit topology and enables independent control of the quality factor Q using single passive element. The circuit requires the minimal number of active and passive elements with no conditions for component matching. By slight modification of the proposed filter structure, the new DBTA-based sinusoidal oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded passive elements. The proposed sinusoidal oscillator employs only grounded capacitors. The passive and active sensitivities of all the proposed circuit configurations are low. PSPICE simulations using a BJT realisation of DBTA and experimental results based on commercially available amplifiers OPA860 and MAX436 are included, which prove the workability of the proposed circuits.     

Electronically tunable sinusoidal oscillator circuit with current and voltage outputs

A new circuit configuration for the realisation of an electronically tunable sinusoidal oscillator is presented. The proposed circuit uses only one current backward transconductance amplifier (CBTA), two grounded capacitors and one resistor. Using current controlled CBTA (CC-CBTA) instead of the CBTA, the resistor can be completely removed. It has also current-mode (CM) and voltage-mode (VM) outputs, simultaneously. The workability of the proposed structure has been demonstrated by both simulation and experimental results.     

基于MOCCCII的双模式二阶通用滤波器

提出了一种基于多输出端口电流控制电流传输器(MOCCCII,multiple outputs current controlled conveyor)的双模式二阶通用滤波器,该滤波器结构简单,仅由5个有源器件、2个接地电容构成, 无须外接电阻.该电路在不改变内部电路结构的情况下能实现电压模式和电流模式滤波器,且每一种工作模式都能实现高通、低通、带通等多种滤波功能,因此该电路具有通用性.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.     

Single MIMO-OTA and single-grounded-capacitor-based first-order allpass filter design

A novel first-order voltage-mode allpass (AP) filter employing a single multiple-input-multiple-output operational-transconductance-amplifier (MIMO-OTA) and a single grounded capacitor is introduced in this article. Compared to the corresponding already published topologies, the offered benefits are as follows: it employs minimum number of active and passive components; the only capacitor is grounded, which is good for a monolithic integration of an IC; and the absence of any matching condition for its realisability. The performance of the proposed circuit has been evaluated through simulation results, utilising the analogue design environment of Cadence software.     

一种新颖的电压模式通用二阶CCII滤波器设计

提出了一种基于电流传送器的电压模式通用二阶滤波器电路。该电路由三个电流传送器（CCII＋／-）、两个电容、三个电阻构成，它能实现二阶低通、带通、高通、陷波、全通滤波函数。分析了该电路的电压传输函数及电路参数，并用PSPICE对该电路进行了仿真，仿真结果表明，该电路设计正确，电路结构简单，所用元器件少。     

一种具有快速电压跟随和宽输出电压范围的电压模式DC-DC降压型变换器

A high switching frequency voltage-mode buck converter with fast voltage-tracking speed and wide output voltage range has been proposed. A novel error amplifier （EA） is presented to achieve a high DC gain and get high phase margin, including a resistor and capacitor net, a unit gain block and a high gain block. The investigated converter has been fabricated with GF 0.35 μm CMOS process and can operate at 6 MHz with the output voltage range from 0.6 to 3.4 V. The experimental results show that the voltage-tracking speed can achieve 8.8 μs/V for up-tracking and 6 μs/V for down-tracking. Besides, the recovery time is less than 8 μs while the load current suddenly changes 400 mA.     

基于OTA的通用双二阶滤波器设计

在跨导运算放大器（OTA,Operational Transconductance Amplifier）器件特性的基础上,提出了一种采用OTA构成的电压模式三输入单输出通用双二阶滤波电路,该电路由4个OTA、2个电容构成。通过选择不同的输入端口,它可以实现二阶低通、带通、高通、陷波、全通5种滤波功能,通过分析该电路的传输函数可知,该电路的灵敏度低,对该电路用PSPICE进行了仿真,仿真结果表明该电路设计正确。