An approach to modelling DC-DC converter circuits using graph theoretic concepts

An approach to modelling DC-DC converter circuits based on graph theoretic concepts is discussed in this paper. the DC-DC converter circuits are treated as networks containing switches, with the magnitudes of their associated eigenvalues much smaller than the switching frequency. the procedure for modelling this class of networks essentially involves separating the original network into two N-port networks, one containing those branches responsible for all phenomena peculiar to the switching action and the other containing the remaining branches of the network. the two N-port networks thus formed lead to a systematic and convenient way of developing low-frequency circuit models for DC-DC converter circuits.     

A memristive dual-slope A/D converter

As an emerging device, memristor has several excellent properties like changeable memristance, nonvolatility, and nanoscale. Based on complementary metal-oxide-semiconductor (CMOS) dual-slope analog-to-digital (A/D) converter, this paper proposes a memristive dual-slope A/D converter. Owing to the usage of memristor, the proposed memristive A/D converter not only has more compact circuit structure and simpler control timing than the CMOS one but also has advantages over the existing memristive conversion circuits in circuit design and application. For the memristive A/D converter, a conversion process consists of two count procedures. By means of controlling the memristance change in the two count procedures, the A/D converter converts an analog signal to the corresponding digital count value. Meanwhile, the conversion result is inferred according to the circuit structure of the A/D converter. Then, combining the conversion process and PSPICE simulation, this paper analyzes the anti-interference performance of the A/D converter. Further, the robustness of the A/D converter is presented, applying the similar analysis methods. The analysis results demonstrate that the proposed A/D converter has good anti-interference and robustness performances.     

A serial charge redistribution logarithmic A/D converter

The present paper describes the design and prototype construction of a serial charge redistribution logarithmic A/D converter (LADC). the LADC uses only two capacitors and has an eight-bit digital word. It directly converts the input to logarithmic code and is suitable for use with digital systems implementing the sign-log number system. the conversion is completed in 128 steps (clock cycles). the input dynamic range is four decades and the relative error is 3.7 per cent. A capacitor ratio accuracy of 0.4 per cent is required to keep conversion errors within 1 LSB.     

一种提高DSP芯片内置A /D转换器精度的方法

模数转换模块是微机保护硬件的重要组成部分。提出了一种提高TMS320LF2407DSP芯片内置A/D转换器精度的方法,并对其误差进行了分析。该方法根据输入的模拟信号的幅值判断由不同的事件管理器触发相应的排序器,选择模拟转换通道,对模拟输入量进行模/数变换。分析证明,该方法具有较好的精度,可满足工程要求,且硬件实现简单。     

一种提高DSP芯片内置A/D转换器精度的方法

模数转换模块是微机保护硬件的重要组成部分.提出了一种提高TMS320LF2407 DSP芯片内置A/D转换器精度的方法,并对其误差进行了分析.该方法根据输入的模拟信号的幅值判断由不同的事件管理器触发相应的排序器,选择模拟转换通道,对模拟输入量进行模/数变换.分析证明,该方法具有较好的精度,可满足工程要求,且硬件实现简单.     

数模转换器的EWB仿真分析与研究

为解决实际电子产品设计和开发过程中的问题,以EWB仿真软件为例,详细讨论了D/A数模转换电路和集成DAC芯片的仿真。根据仿真结果得知:温度的影响:当温度从0℃升高到100℃的过程中,输出电压快速升高,最后波动幅度逐渐减小,趋于恒定;电路参数的影响:当R1从1kΩ线性增大到10kΩ,初始输出线性升高,后由于非线性失真趋于恒定,因此设计倒T形电路网络D/A转换器时需注意电阻的精确度。对于集成DAC,当数字输入值较高时转换精度下降。     

A/D变换器性能的分析与测量

讨论了A／D变换器的性能参数;深入分析了A／D变换器的噪声组成及其影响因素;介绍了信噪比、谐波失真度、有效位数的测量与实现。     

MAX1415／1416A／D转换器的原理及其应用

介绍了MAX1415/1416A/D转换器的特征、工作原理及其与单片机的接口技术。     

A／D转换器的动态非线性模型辨识

本文提出了一种辨识A/D转换器动态非线性参数模型的方法。A/D转换器的动态模型由Volterra级数描述。用高阶谱很容易辨识出Volterra核。计算机模拟证明了方法的正确性。     

串行A/D转换器TLC2543原理及应用

介绍了一种多通道高精度串行A／D转换器TLC2543的主要特点、工作原理和实际应用。     

流水线模数转换器设计

设计了一款14位、125MS/s流水线模数转换器(ADC)。通过前端采样/保持电路(SHA)消除对输入信号采样的孔径误差,采用4位结构的首级转换电路提高ADC线性性能,设计了带输入缓冲的栅压自举开关以缓解首级转换电路输入采样开关中自举电容对SHA的负载效应,流水线ADC级间通过逐级按比例缩减策略使功耗得到节省。该设计采用0.18μm 1P5MCMOS工艺,ADC版图面积2.3 mm×1.4 mm。Spectre后仿真结果显示,采样频率125 MHz、输入信号在接近Nyquist频率(61MHz)处时信号噪声畸变比(SNDR)和无杂散动态范围(SFDR)可分别达到75.7 dB和85.9 dB。在1.8V电源电压下,ADC核心部分功耗为263 mW。     

∑-△A/D转换器的原理及分析

本文简介了∑-△A/D转换器的原理,初步推导了∑-△A/D转换器的数学变换过程及其量化误差成型过程,定性分析了影响∑-△A/D转换器测量精度的因素.     

AVR单片机与串行A/D的SPI接口设计

为了解决信号采集系统的同步串行通讯问题,在理解AVR单片机SPI接口的通讯原理和方法的基础上,分析了AVR单片机SPI接口的工作过程,设计了AVR单片机和串行A/D转换器的同步串行通讯接口,并用程序描述了SPI接口通讯的过程,实现了AVR单片机通过SPI接口与串行A/D转换器之间的数据通讯.最后,用实验和数据分析验证了设计方案的可行性.     

称重测控系统的A/D转换电路设计

针对AD7706芯片组成的A/D转换电路硬件、软件的设计方法进行阐述与论证。实践表明,基于AD7706高精度A/D转换电路组成的称重单片机测控系统,具有测量精度高、测量速度较快、性能稳定等特点。     

TMS320VC5402与模数转换器AD1674的接口设计

DSP系统是一种新型的快速数字处理系统,处理的信号是数字信号,模数转换是DSP必需的外围电路。介绍了高性能定点DSP芯片TMS320VC5402和ADC芯片AD1674的主要特点,设计了基于TMS320VC5402与AD1674的接口电路及软件编程。     

电子式互感器模/数转换电路的设计与应用

介绍了一种基于TI公司TMS320LF2407的DSP芯片和14 bit数据转换芯片MAX125的电子式互感器模/数转换电路设计。详细介绍了硬件和软件的实现方法,并将该设计成果应用到数字化变电站中,得到实际的运行状况。该设计可以实现多个通道同时采集,具有速度快、处理能力强以及功耗低等优点,能够满足数字化变电站监控实时性、精确性和处理算法的复杂性等要求。     

Matrix converter control using direct AC/AC conversion approach to reduce output voltage harmonics

This paper presents a control scheme for matrix converters for reducing the output voltage harmonics. The proposed control scheme is based on the direct AC/AC conversion approach and the carrier‐based PWM control to obtain the constant switching frequency. The proposed scheme can achieve simultaneous control of both the output voltage and the input power factor. A feature of the proposed control scheme is the reduction of both the output voltage harmonics and the number of instances of commutations. The effectiveness of the proposed control algorithm for a matrix converter has been verified by simulations. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 61–72, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20550     

Upper bound on the number of equivalent oscillator-notch filter circuits: A group theoretic approach

It is shown that the problem of synthesizing RC oscillators and notch filters can be reduced to a group theoretic problem of finding isomorphisms. the required group is identified as the Klein group. From this it is also shown that there is a sharp upper bound on the number of new circuits that can be generated from the knowledge of a parent circuit. This bound is independent of the number of branches and internal nodes.     

高速DSP与串行A/D转换器TLC2558接口的设计

根据高速定点DSP芯片TMS320F206的特点，提出了使用串行A/D转换器TLC2558作为DSP系统的模拟量输入部分，解决了以往基于并行数据传输的A/D转换器不能与高速DSP进行很好配合的问题，在此基础上设计了DSP与串行A/D转换器连接的硬件电路，并就A/D转换的软件设计时应注意的问题进行了探讨。