A Current-Mode DC-DC Buck Converter with High Stability and Fast Dynamic Response

A current-mode DC-DC buck converter with high stability is presented. The loop gain＇s expression of the current-mode converter is derived by employing an advanced model of a current-mode control converter. After analyzing the loop gain＇s expression, which illustrates the method of selecting suitable frequency compensation for the control loop,a novel pole-zero tracking frequency compensation is proposed. Based on theoretical analysis, a DC-DC buck converter with high stability is designed with 0.5μm-CMOS technology. The simulated results reveal that the stability of the converter is independent of the load current and the input voltage. Moreover,the converter provides a full load transient response setting time of less than 5μs and overshoots and undershoots of less than 30mV.

DESIGN OF TERNARY CURRENT-MODE CMOS CIRCUITS BASED ON SWITCH-SIGNAL THEORY

By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is suitable to current-mode CMOS circuits is proposed. Thecircuits, such as ternary full-adder etc., designed by using this theory have simpler circuit struc-tures and correct logic functions. It is confirmed that this theory is efficient in guiding the logicdesign of current-mode CMOS circuits at switch level.

A Synthesis of Electronically Controllable Current-Mode PI, PD and PID Controllers Employing CCCDBAs

This paper presents a synthesis of current-mode PI, PD and PID controllers employing current controlled current differential buffer amplifiers (CCCDBAs). The features of these controllers are that: the output parameters can be electronically/independently controlled by adjusting corresponding bias currents in the proportional, integral, and deviation controllers;circuit description of the PID controller is simply formulated, it consists of four CCCDBAs cooperating with two grounded capacitors, and PI and PD controllers are composed of three CCCCDBAs and a grounded capacitor. Without any external resistor, the proposed circuits are very suitable to develop into integrated circuit architecture. The given results from the PSpice simulation agree well with the theoretical anticipation. The approximate power consumption in a closed loop control system consisting of the PI, PD and PID controller with low-pass filter passive plant are 4.03 mW, 4.85 mW and 5.71 mW, respectively, at ±1.5 V power supply voltages.

Electronically Controllable Fully-Uncoupled Explicit Current-Mode Quadrature Oscillator Using VDTAs and Grounded Capacitors

An electronically controllable fully uncoupled explicit current-mode quadrature oscillator employing Voltage Differencing Transconductance Amplifiers (VDTAs) as active elements has been presented. The proposed configuration employs two VDTAs along with grounded capacitors and offers the following advantageous features 1) fully and electronically independent control of condition of oscillation (CO) and frequency of oscillation (FO);2) explicit current-mode quadrature oscillations;and 3) low active and passive sensitivities. The workability of proposed configuration has been demonstrated by PSPICE simulations with TSMC CMOS 0.18 μm process parameters.

An Active-Only Temperature-Insensitive Current-Mode Biquad Filter Based on Differentiator Structures Employing CCCCTAs

This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.

Universal Current-Controlled Current-Mode Biquad Filter Employing MO-CCCCTAs and Grounded Capacitors

This paper presents a universal current-controlled current-mode biquad filter employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs). The proposed filter employs only three MO- CCCCTAs and two grounded capacitors. The proposed filter can simultaneously realize low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) responses in current form by choosing appropriate current output branches. In addition, the pole frequency and quality factor of the proposed filter circuit can be tuned independently and electronically over the wide range by adjusting the external bias currents. The circuit possesses low active and passive sensitivity performance. The validity of proposed filter is verified through PSPICE simulations.

Voltage/Current-Mode Multifunction Filters Using One Current Feedback Amplifier and Grounded Capacitors

One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.

Inductor Current Sampled Feedback Control of Chaos in Current-Mode Boost Converter

A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.

A VERSATILE CURRENT-MODE BIQUAD USING OPERATIONAL AMPLIFIERS

A versatile current-mode biquadratic filter using three operational amplifiers and nine passive elements is proposed. By suitably choosing the output branch, lowpass, bandpass, highpass, bandstop and allpass transfer functions are realized simultaneously without changing the circuit configuration and elements. Two circuits, one is for low frequency application and the other for high frequency, are proposed. The center frequency, quality factor and gain constants of the circuit can be tuned independently. Simulated results show that the circuits work successfully.

DESIGN OF SYMMETRIC TERNARY CURRENT-MODE CMOS CIRCUITS

By applying switch-signal theory, the theory of transmission current-switches based on symmetric ternary logic is proposed, this theory is suitable to design symmetric ternary current-mode CMOS circuits. The symmetric ternary current-mode CMOS circuits designed by using this theory not only have simpler circuit structures and correct logic functions, but also can process bidirectional signals.

THE DESIGN OF ACTIVE CURRENT-MODE FILTER WITH STATE VARIABLE METHOD

Basing on the state variable method, a block diagram of the current-mode biquad active circuit was proposed, whose integrators were realized using three kinds of active elements such as operational amplifier, second generation current conveyors and operational transconduc-tance amplifiers-electric capacity. The characteristics of each circuit were analyzed.

DOCCII-based electronically tunable current-mode biquadratic filters

A complete state variable current-mode biquadratic filter built by duo-output CCII (DOCCII) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCII. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.

Low Input and High Output Impedances Current-Mode First-Order Allpass Filter Employing Grounded Passive Components

A current-mode low input and high output impedances first-order allpass filter using two multiple output second-generation current conveyors (MOCCIIs), one grounded capacitor and one grounded resistor is presented. The suggested filter uses a canonical number of passive components without requiring any component matching condition. The frequency responses simulation results of the proposed filter confirm the theoretical analysis.

Universal Current-Mode Biquad Employing Dual Output Current Conveyors and MO-CCCA with Grounded Passive Elements

A new universal multiple input multiple output (MIMO) type current-mode biquad employing two dual output current conveyors (DOCCII), one multiple output current controlled current amplifier (MOCCCA) and four passive grounded elements is proposed which can realize all the five basic filtering functions namely, low-pass (LP), high-pass (HP), band-pass (BP), band-stop (BR) and all-pass (AP) in current mode from the same configuration. The centre frequency can be set by the passive elements of the circuit and the quality factor Q0 is electronically tunable through bias currents of the MOCCCA. Therefore, the biquad filter has independent tenability for the and Q0. The active and passive sensitivities of Q0 and are low. The workability of the new configuration has been demonstrated by PSPICE simulation results based upon a CMOS CCII in0.35μm technology.

数字下变频实现技术研究

目前的无线电正朝着软件无线电方向发展,因此如何用实现高速射频采样数据下变频到低速基带就成了一个关键问题。本文在简要介绍软件无线电的基础上,提出了利用多速率信号处理和高效数字抽取滤波器的几种实现方法。

零中频宽带数字接收机方案的设计

通过应用软件无线电的思想,搭建了一个用于宽带中频(射频)信号接收的硬件平台,将处于中频(射频)段的高速宽带的模拟信号以下变频的方式变成处于基带的数字信号,同时以正交I,Q信号的形式输出,以便于后续的DSP对其进行软件算法的调解和处理。该接收机设计输出的单通道带宽可达20MHz,适合宽带中频(射频)信号的接收,是目前硬件条件受到限制的情况下,宽带中频(射频)信号接收方法中一个可行的实施方案。

任意中频带通信号多相数字下变频方法

基于多相结构的数字下变频方法由于其可实现性强,抗干扰能力强等优点,在电子系统软件化的趋势中得到越来越多的重视。其缺点是存在信号接收盲区。该文在多相滤波数字下变频方法的基础之上,提出了一种改进方法。该方法在不改变原有下变频器结构的前提下,实现监视带内任意中频位置带通信号接收,消除接收盲区。

宽带无线接收机射频前端结构研究与设计

论证了宽带无线接收机宜采用上边注入、固定中频的二次正交混频低中频结构.文中推导出单双正交与双双正交这两种二次正交混频结构中分别存在4种镜像抑制比及这4种镜像抑制比与其结构中的幅度失配ΔA或相位失配Δθ之间的定量关系.两种结构的性能比较表明,宽带无线接收机射频前端更适合采用单双正交结构.为提高系统的镜像抑制性能,射频前端在单双正交结构的基础上添加两个模块:射频滤波器与第2次混频之前的多相滤波器.最后,给出了整个射频前端系统的镜像抑制性能关系式,并给出一个设计实例(DRM接收机射频前端).MATLAB仿真结果表明,本射频前端结构具有良好的镜像抑制性能(当-10°≤Δθ≤10,°-0.1≤ΔA≤0.1时,4个镜像抑制比IRR≥61.16 dB),结合低中频结构固有的便于高集成度,支持多通信标准,且可避免寄生低频噪声影响等特点,使之成为实现宽带无线接收机的理想结构之一.

基于软件无线电技术的核四极矩共振谱仪设计

介绍了软件无线电技术的基本原理 ,分析了全数字化核四极矩共振谱仪的设计要求 ,讨论了设计时在软件、硬件方面的一些考虑 。

基于全流程并行加速的改进数字下变频器设计

针对宽带通信雷达探测系统中高速率数据处理难度较大的问题,设计了一种全流程并行化处理的高速率数字下变频器,混频模块采用并行化的流水线坐标旋转数字计算机(CORDIC)对来自A/D的高速采样数据进行分组处理,以降低单个通道的数据率;抽取滤波模块采用多相滤波器进一步将高阶卷积网络进行并行化分解,减少不必要的乘累加运算。实验结果表明:最大处理速率由原先的131 MHz提高到了255 MHz,改进设计利用现有硬件条件大幅度提高了处理速度,减少了通带内信号的衰减。