有机薄膜晶体管直流电流-电压模型的研究

通过对有机薄膜晶体管(OTFT)电流-电压特性的研究,建立了一种用于电路模拟的仿真程序(SPICE)的OTFT直流电流-电压模型,所用的参数都可从实验特性曲线中提取。对一种基于并五苯(Pentacene)的底栅顶接触(TC)结构的OTFT的实验曲线进行参数提取,并利用所得的参数与建立的模型进行仿真,得到的输出特性和转移特性曲线与实验结果无论在线性区还是在饱和区都具有较强的一致性,验证了本文所建模型及参数的准确性。建立的模型能够准确描述OTFT的直流特性,可用于有机电路的SPICE仿真。     

Analog inner product operations for image compression in 0.35-μm CMOS

We propose a new model for analyzing the sensitivity of inner products to CMOS analog hardware implementation. It is derived from Spice simulations of the circuits to be implemented, and it is required for the design of analog image compression systems based on vector quantization at the focal plane of CMOS imaging sensors. The model is shown to be equivalent to a simpler and previously introduced theoretical model, if the errors caused by the fabrication process are around 6%. For 1.5% errors, the results differ from the theoretical predictions made by the previous model. Image compression results obtained with a prototype circuit fabricated in a 0.35-μm CMOS process are presented, and show close agreement with both theoretical and simulation predictions.     

Modelling and simulation of gate leakage currents of solution-processed OTFT

This paper presents a model for the simulation of gate leakage currents within organic thin film transistors. These unintended currents act as loads within integrated electronic circuits and thereby can have a huge impact on its functionality. Simulation of these currents is important in order to design and manufacture high performance organic electronics circuits of high complexity. We show the influence of gate leakage currents on signals within a circuit. A model for electrical simulations is developed, which is based on defects within the dielectric layer. Only two new parameters need to be determined, they describe the size and amount of defects. The improvement of simulation by this model is verified by comparison of measurements and simulations.     

A practical method for friction identification in hydraulic actuators

Friction in hydraulic actuators can be described using nonlinear, velocity dependent models. In this paper, the friction is described by an exponential Stribeck friction model. An iterative algorithm is presented to identify the friction model parameters. The method fits two lines on the experimental data relating steady-state velocities to actuator pressure differentials. The parameters of the fitted lines are obtained using an iterative optimization technique. Based on the obtained parameters, the original nonlinear friction model parameters are completely reconstructed. The proposed method is validated by building a simulation model for a valve-controlled hydraulic system in which the friction is modeled based on the method described here. The proposed method can be used in practical situations, whereby fast and reliable identification of major parameters of the friction in hydraulic actuators is needed with easy to obtained pressure measurements.     

Statistical estimation of delay-dependent switching activities inembedded CMOS combinational circuits

This paper describes a new procedure to estimate the delay-dependent switching activities in CMOS combinational circuits. The procedure is based on analytic and statistical approaches to take advantage of their time-efficiency over conventional event-driven simulation tools. For this study, combinational circuits driven by discrete-time logic signals are considered. By focusing on a specific class of combinational circuits, the transitional effects can be analyzed more accurately by considering some of the delay effects neglected in previous studies, Also, to model the delay-dependent effects, statistical properties such as the pattern probability, the propagation probability, and the distribution of the propagation delay of switching activities are defined and evaluated. The simulation results on benchmark circuits indicate that the proposed procedure significantly speeds up the estimation process in comparison to the conventional event-driven simulators. The reliability issues in the aspect of switching activities are briefly discussed     

Reliability of majority voting based VLSI fault-tolerant circuits

The effect of compensating module faults on the reliability of majority voting based VLSI fault-tolerant circuits is investigated using a fault injection simulation method. This simulation method facilitates consideration of multiple faults in the replicated circuit modules as well as the majority voting circuits to account for the fact that, in VLSI implementations, the majority voting circuits are constructed from components of the same reliability as those used to construct the circuit modules. From the fault injection simulation, a survivability distribution is obtained which, when combined with an area overhead expression, leads to a more accurate reliability model for majority voting based VLSI fault-tolerant circuits. The new model is extended to facilitate the calculation of reliability of fault-tolerant circuits which have sustained faults but continue to operate properly. Analysis of the reliability model indicates that, for some circuits, the reliability obtained with majority voting techniques is significantly greater than predicted by any previous model     

A behavioral circuit simulation model for high-power GaAs Schottky diodes

This paper proposes a physically based behavioral circuit simulation model for high-power GaAs Schottky diodes which is valid over all regions of operation. No conditional statements are needed to define the regions of operation. A new and more accurate method of obtaining depletion capacitance model parameters from the measured capacitance values is proposed. A simple current- and temperature-dependent resistance model is used to model the nonlinear diode resistance as well as contact and packaging resistances. The validity of the model is demonstrated under various DC and transient switching conditions. Simulation results are compared with the experimental data obtained from a 200 V GaAs Schottky diode. The diode model is tested at various temperatures in different test circuits and the simulation results are shown to be in excellent agreement with the measured data under static and dynamic switching conditions. The model can be easily implemented in other circuit simulators.<>     

DTMOS Technique for Low-Voltage Analog Circuits

In this paper, the application of dynamic threshold MOS (DTMOS) technique for low-voltage analog circuits is explored. The body terminal of PMOS transistors in bulk CMOS technology can be used as the forth terminal to enhance the performance of low-voltage analog circuits. To show the effectiveness of this technique, we have designed a continuous time common mode feedback (CMFB) circuit for a sub 1-V opamp and a new sub 1-V, 1-bit quantizer. A 0.8-V opamp with embedded CMFB and a 0.8-V, 1-bit quantizer for low-voltage DeltaSigma modulators are implemented in 0.18-mum CMOS technology. The simulation results as well as the measurement data of these blocks are presented in this paper     

Structural Modeling and Performance Analysis of Rotary Circuit in Directional Drilling Rig Based on Load Sensing Technology

Aim at improving the energy saving and transmission efficiency of directional drilling rig, the load sensing technology and constant-pressure variable technique are adopted to enable the system to provide the required pressure and flow rate according to the load variation. In order to research the dynamic characteristics of hydraulic control systems, the background and working principle of the load sensing technology were introduced. The dynamic mathematical model of load sensing system is established based on the hydraulic principle. The directional drilling rig mainly consists of two basic circuits: rotary circuit and feed circuit. The dynamic characteristics of rotary circuit are mainly studied. In addition, the hydraulic system of kilometres directional rig is simulated with the software of AMESim. The simulation results show that the load sensing pump could output its required flow and outlet pressure adapted to the load pressure in real time, thus effectively improving the efficiency of the hydraulic system. Furthermore, to verify the validity of the mathematical model and the simulation analysis, an experimental platform of the load sensing hydraulic system was built. The dynamic performance test of load sensing hydraulic system was performed by using the platform. The experimental results demonstrated that the load sensing hydraulic system could output its required flow and pressure when the working condition changed. Finally, they also illustrate the validity of the proposed approach.     

Transistor-tunnel-diode ternary-logic circuits

Two new basic circuits for ternary-logical operations are described. Analogue simulation and experimental measurements confirm that the switching speeds of the ternary circuits can be comparable with those in similar binary circuits. It is concluded that a marginal improvement in processing rate may be achieved with ternary logic using transistor-tunnel-diode logic circuits.     

实用线性IC电路模拟系统的开发

本文介绍了可广泛用于IC电路设计的线性IC电路模拟系统。主要叙述了电路模拟软件实用功能设计,新的器件模型的建立;叙述了把电路模拟与实际工艺结合起来的参数提取程序的设计。     

A novel simulation technique for testing analog ICs

The increasing demand for reliable and high quality mixed-signal integrated circuits necessitates a defect-oriented testing methodology. Thereby fault simulation (FS) is essential for test stimuli generation and test quality assessment. Due to the high computational effort needed, analog FS is becoming a critical factor in testing mixed-signal ICs. This paper provides a new accelerated FS approach. It is based on an improved application of the Newton–Raphson method in the analysis of similarly behaving circuits. Metrics for measuring circuits' behavior similarity are presented. The new techniques are implemented in an experimental FS tool. For sample circuits, experimental results are presented and discussed.     

激光驱动的1维准等熵压缩数值计算

为了研究激光辐射驱动平面材料的准等熵压缩过程,基于激光间接驱动的1维平面应力装载过程和熵增的数学模型,用拉格朗日法计算了平面材料在1维压缩情况下不同位置的压缩比、应力和熵增随时间的变化过程,并用已有的实验数据进行计算,数值计算结果与文献报道的结果符合得很好。结果表明,粒子速度、材料比热容、Hugoniot参量和Grüneisen系数是表征1维准等熵压缩的基本参量;综合运用这些参量可以判断等熵压缩过程。     

基于DSP控制的位控液压伺服系统电模拟仿真器

为了研究位控液压伺服系统的运动特性,笔者在系统数学模型的基础上设计了研究对象的电模拟仿真器,并使用DSP作为数字控制器对位控液压系统的控制进行半物理仿真实验研究.实验结果证明,该实验系统可以验证控制算法,可以扩展控制效果,因此是一个有效的实验研究平台.     

Optimal asymmetrical back plane biasing for energy efficient digital circuits in 28 nm UTBB FD-SOI

In this work we propose an optimal back plane biasing (OBB) scheme to be used in a UTBB FD SOI technology that minimizes the energy per operation consumption of sub threshold digital CMOS circuits. By using this OBB scheme, simulations show that more than 30% energy savings can be obtained with low threshold voltage (LVT) devices in comparison with classic symmetric back plane biasing (SBB) schemes. Additionally, this OBB scheme allows to adjust the performance of the circuit with very small energy penalties. A very simple and intuitive model, for sub threshold digital CMOS circuits, was developed to justify the benefits obtained by OBB. The results predicted by the model are confirmed with extensive simulation results. We show that the OBB approach can be applied easily to a given circuit just based on the information provided by a logic simulation of the circuit (or even an analysis of its structure) and simple electrical simulations of the pMOS and nMOS transistors. Finally, we show that the variability in the energy consumption is improved by using OBB and suggests that new sizing methodologies must be studied to fully benefit from the wide back plane voltage range available in UTBB FD SOI technology for the design of robust energy efficient digital circuits.     

模拟电子电路虚拟实验平台的设计与实现

提出了用于模拟电子电路实验教学的虚拟实验平台，该平台可以实现模拟电子电路实验实际操作与计算机模拟分析相结合的实验教学方式，同时应用虚拟仪器技术对电路进行测试和故障查找，从而培养学生应用EDA技术设计电路系统和实际操作的能力。     

新颖的含PFC的PWM ZVS AC-DC变换器

提出了一种新的具有功率因数补偿(PFC)功能的零电压开关(ZVS)AC-DC变换器,该变换器基于不连续导电模式(DCM)下的Boost环节实现PFC功能,但其具有ZVS机制,从而解决了DCM下因开关关断大的峰值电流引起的关断损耗高、EMI严重的问题,同时还消除了由于开关的寄生电容引起的开通损耗.该变换器可以采用通用控制芯片并工作在PWM模式.文中分析了提出变换器的工作原理,并给出了基本设计原则.模拟和实验结果证明了提出的电路是可行的.     

Model for Transient Fault Susceptibility of Combinational Circuits

Transient faults (TFs) are increasingly affecting microelectronic devices as their size decreases. During the design phase, the robustness of circuits for high reliability applications with respect to this kind of faults is generally validated through simulations. However, traditional electrical level simulators are too slow for the task of simulating the effects of TFs on large circuits. In this paper, we present a new model to estimate accurately the possible propagation of transient fault-due glitches through a CMOS combinational circuit. We will show how the proposed model can be applied in order to estimate the TF susceptibility of a circuit by simply considering the propagation delay of the datapath. Therefore, the proposed model is suitable to be used into a new simulation tool able to provide good accuracy, while significantly speeding up simulations, with respect to electrical level simulation. In particular, our model allows approximately 90% accuracy with respect to HSPICE simulations.     

Time-domain modeling of high-speed interconnects by modified methodof characteristics

In this paper, a new model of lossy transmission lines is presented for the time-domain simulation of high-speed interconnects. This model is based on the modified method of characteristics (MMC). The characteristic functions are first approximated by applying lower order Taylor series in the frequency domain, and then a set of simple recursive formulas are obtained in the time domain. The formulas, which involve tracking performances between two ends of a transmission line, are similar to those derived by the method of characteristics for lossless and undistorted lossy transmission lines. The algorithm, based on the proposed MMC model, can efficiently evaluate transient responses of high-speed interconnects. It only uses the quantities at two ends of the lines, requiring less computation time and less memory space than required by other methods. Examples indicate that the new method has high accuracy and is very efficient for the time-domain simulation of interconnects in high-speed integrated circuits     

Methods of functional-logic simulation of radiation-induced failures of electronic systems based on the fuzzy state machine model

The methods of functional-logic simulation of radiation-induced failures of electronic systems based on the Brauer fuzzy state machine model are presented. Recommendations for methods of radiationinduced failure prediction in the electronic component base are given. Theoretical and experimental results for the radiation fault tolerance of 1617 large-scale integrated circuits based on complementary metal–oxide–semiconductor structures are given as an example.