基于嵌入式系统的晶体管特性图示仪设计

发布时间：2018-01-16 16:04

本文关键词：基于嵌入式系统的晶体管特性图示仪设计　出处：《合肥工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：晶体管作为重要的电子元器件,既是整个电子行业的基础,同时也深刻地影响着行业的发展。晶体管特性图示仪作为测量测试仪器,在晶体管的筛选使用过程中发挥着重要作用。传统晶体管特性图示仪是基于模拟电子线路的纯硬件设备,缺少数字化接口,同时体积较大。随着嵌入式系统的应用以及微电子技术的发展,为晶体管特性图示仪的数字化、网络化和智能化发展提供了技术支撑,本文研究基于嵌入式处理器的晶体管特性图示仪设计方法,能够实现相关参数的自动测量、计算与显示,为高校电子信息类相关专业提供信息化实验教学设备。本文简介晶体管特性图示仪原理、单元电路组成及结构特点,基于嵌入式微控制器STM32F103设计了一种数字化的晶体管特性图示仪。给出图示仪硬件体系结构设计,整个系统包括微控制器单元模块、信号发生电路模块、信号采集和调理模块以及显示模块,重点介绍信号发生电路和数据采集电路的设计,其中信号发生电路由阶梯电流源、阶梯电压源以及扫描电压源三个部分组成,集电极弱电流信号(精密采样电阻端电压)通过仪表放大器放大处理后进行采样。软件上基于Keil μ Vision集成开发环境实现测量控制功能,微控制器单元通过SPI接口控制数字电位器接入电路的阻值而产生基极阶梯电流信号,通过DAC输出可调模拟电压产生集电极扫描电压信号,采用内置12位逐次逼近型ADC进行基极和集电极电压采样,采用中位值平均滤波算法对连续多次采样值进行运算,提高测量精度,通过可变静态存储控制器总线驱动LCD,对于待测晶体管输入输出特性曲线的显示采用描点法实现。同时,还基于Lab VIEW设计了上位机程序,通过网口向微控制器单元发送控制命令或者接收来自它的采样数据并保存。本文最后给出各模块测试数据及系统实验结果,结果表明设计的嵌入式晶体管特性图示仪正常运行,阶梯电流源产生分辨率为0.1μA的0-160μA电流,扫描电压源产生分辨率为8mV的0-30V电压,通过与实验室现有图示仪对比,其输出特性测量误差为0.24%,精度较高,同时该图示仪体积小、成本低,对测试结果可以进行数字化处理。
[Abstract]:As an important electronic device, transistor is not only the foundation of the whole electronic industry, but also has a profound impact on the development of the industry. Traditional transistor characteristic grapher is a pure hardware device based on analog electronic circuit and lacks digital interface. With the application of embedded system and the development of microelectronic technology, it provides technical support for the digitization, networking and intelligent development of transistor characteristic grapher. In this paper, the design method of transistor characteristic grapher based on embedded processor is studied, which can realize the automatic measurement, calculation and display of related parameters. This paper introduces the principle of transistor characteristic graph instrument, unit circuit composition and structure characteristics. Based on the embedded microcontroller STM32F103, a digital transistor characteristic grapher is designed, and the hardware architecture of the instrument is designed. The whole system includes the module of the microcontroller unit. Signal generation circuit module, signal acquisition and conditioning module and display module. The design of signal generation circuit and data acquisition circuit is introduced, in which the signal generation circuit is composed of step current source. The step voltage source and the scanning voltage source are composed of three parts. The collector weak current signal (precision sampling resistor terminal voltage) is amplified by the instrument amplifier and sampled. The software realizes the function of measurement and control based on Keil 渭 Vision integrated development environment. The microcontroller unit controls the resistance of the digital potentiometer access circuit through the SPI interface to generate the base step current signal, and the collector scan voltage signal is generated by the DAC output adjustable analog voltage. The embedded 12-bit successive approximation ADC is used to sample the base and collector voltage, and the median average filter algorithm is used to calculate the continuous multiple sampling values to improve the measurement accuracy. LCD is driven by variable static memory controller bus, and the display of input and output characteristic curve of transistors to be tested is realized by drawing point method. At the same time, the upper computer program is designed based on Lab VIEW. The control command is sent to the microcontroller unit through the network interface or the sampling data from it is received and saved. Finally, the test data of each module and the experimental results of the system are given. The results show that the embedded transistor characteristic grapher works normally, and the step current source generates 0-160 渭 A current with a resolution of 0.1 渭 A. The scanning voltage source produces 0-30V voltage with a resolution of 8mV. By comparing with the existing graphical instrument in the laboratory, the measuring error of the output characteristic is 0.24, the accuracy is high, and the volume of the instrument is small. Low cost, the test results can be digitally processed.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN32

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