Industrial remote monitoring systems and keep-alivecircuits spend most of their time in standby mode. Manyof these systems also depend on battery power, so powersupply effi ciency in standby state is very IMPortant tomaximize battery life. The LT®8410/-1 high effi ciencyboost converter is ideal for these systems, requiringonly 8.5μA of quiescent current in standby mode. Thedevice integrates high value (12.4M/0.4M) output feedbackresistors, signifi cantly reducing input current whenthe output is in regulation with no load. Other featuresinclude an integrated 40V switch and Schottky diode,output disconnect with current limit, built in soft-start,overvoltage protection and a wide input range, all in atiny 8-pin 2mm × 2mm DFN package.
上传时间： 2013-11-23
上传用户：新手无忧
Handheld electronic devices play a key role in our everydaylives. Because dependability is paramount, handhelds arecarefully engineered with lightweight power sources forreliable use under normal conditions. But no amount ofcareful engineering can prevent the mistreatment theywill undergo at the hands of humans. For example, whathappens when a factory worker drops a bar code scanner,causing the battery to pop out? Such events areelectronically unpredictable, and IMPortant data storedin volatile memory would be lost without some form ofsafety net—namely a short-term power holdup systemthat stores suffi cient energy to supply standby power untilthe battery can be replaced or the data can be stored inpermanent memory.
上传时间： 2013-11-05
上传用户：coeus
光伏发电是未来新能源发电重要方向之一，而光伏变流器是光伏发电系统的核心。介绍一种基于微网理念的光伏变流器设计。以该变流器为核心的光伏发电系统可以看做一个小型的微网系统。该系统能根据外部电网情况，工作于并网模式和离网模式。介绍了该系统的各个组成部件的设计以及变流器主电路部分器件的选型。最后，由实验样机进行测试。试验结果验证了电路拓扑结构及控制方案的可行性，也说明了系统参数设计方法的正确性。 Abstract: Solar Photovoltaic generation is an IMPortant direction of new energy power generation in the future，while photovoltaic converter is the core of photovoltaic generation system. This paper deals with a study on photovoltaic inverter based on the concept of microgrid. This paper describes a system whose core component is the photovoltaic inverter，can work on grid-connected mode or run independently according to the external situation. The paper simply describes the main components of the system. At last，the prototype was produced and tested. Test result has proved feasibility of circuit topology structure and controlling scheme and shown correctness of system parameters.Key words: PV inverter； microgrid； off-grid； storage battery
上传时间： 2014-12-24
上传用户：Shaikh
锁定放大是微弱信号检测的重要手段。基于相关检测理论，利用开关电容的开关实现锁定放大器中乘法器的功能，提出开关电容和积分器相结合以实现相关检测的方法，并设计出一种锁定放大器。该锁定放大器将微弱信号转化为与之相关的方波，通过后续电路得到正比于被测信号的直流电平，为后续采集处理提供方便。测量数据表明锁定放大器前级可将10-6 A的电流转换为10-1 V的电压，后级通过带通滤波器级联可将信号放大1×105倍。该方法在降低噪声的同时，可对微弱信号进行放大，线性度较高、稳定性较好。 Abstract: Lock-in Amplifying（LIA）is one of IMPortant means for weak signal detection. Based on cross-correlation detection theory， switch in the swithched capacitor was used as multiplier of LIA， and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave， then DC proportional to measured signal was obtained through follow-up conditioning circuit， providing convenience for signal acquisition and processing. The measured data shows that the electric current（10-6 A） can be changed into voltage（10-1 V） by LIA， and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the weak signal is amplified. It has the advantages of good linearity and stability.
上传时间： 2013-11-29
上传用户：黑漆漆
When a system designer specifies a nonisolated dc/dc powermodule, considering the needed input voltage range isequally as IMPortant as considering the required performanceattributes and features. Generally, nonisolated moduleshave either a narrow or a wide input voltage range. Narrowinputmodules typically have a nominal input voltage of3.3, 5, or 12 V. For systems that operate from a tightlyregulated input bus—such as those that do not use batterybackup—a narrow-input module is often adequate sincethe input remains fairly stable.Offering greater flexibility, wide-input modules operatewithin a range of 7 to 36 V, which includes the popular12- or 24-V industrial bus. This enables a single module tobe used for generating multiple voltages. These modulesare ideal for industrial controls, HVAC systems, vehicles,medical instrumentation, and other applications that usea loosely regulated distribution bus. In addition, systemspowered by a rectifier/battery charger with lead-acidbattery backup almost always require wide-input modules.System designers who choose power supplies may wantto take a close look at the latest generation of wide-inputdc/dc modules.
标签： Wide-input modules offer dc
上传时间： 2014-12-24
上传用户：dragonhaixm
实时时钟是微机保护装置的重要部件，在讨论PCF8583结构与功能的基础上，提出采用dsPIC33F系列微处理器与串行I2C时钟PCF8583的接口设计方案，给出了相应的接口电路与软件流程。该设计方案结构简单，可靠性高，开发周期短，具有一定的实用与参考价值。所设计的微机保护装置已投入现场运行，效果良好。 Abstract: Real-time clock chip is an IMPortant part in microcomputer protection device.Based on discussing the structure and function of PCF8583，a new interface scheme which uses dsPIC33F microprocessor and serial clock chip（I2C）PCF8583is proposed.The method of the circuit design and the main software flow are introduced in this paper.The scheme has simple structure，higher reliability and shorter exploitation cycle，so has definite practicality or reference value.The microcomputer protection device has been put into operation with better effects.
上传时间： 2013-11-18
上传用户：Thuan
气压是气象监测中的一个重要参数，提出了一种气压数据采集模块设计方案，该模块采用数字气压传感器MS5534B、MSP430单片机MSP430F2272和带实时时钟（RTC）64 KB铁电存储器。通过低功耗软件设计方法以微安级整体平均功耗实现了气压数据的采集和存储，适合电池供电的连续高精度气压采集应用。给出了模块的软硬件设计以及MS5534B的性能指标和使用经验。 Abstract: Air pressure is an IMPortant parameter in weather monitor.This paper futs forward a new design scheme of low power-air pressure data acquisition module.The module uses a digital output barometer sensor MS5534B,MSP430 microcontroller MSP430F2272 and integrated RTC 64KB FRAM,precision air pressure measurement and storage chip.Another point of this module is low power consumption, so it is well suited for battery powered air pressure data acquisition applications. At the same time,the software and hardware deign of module is presented,And the speciaties and use notices of MS5534B are given.
上传时间： 2014-12-27
上传用户：drink！
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标签： SUNPLUSIT Q-Writer 编程工具 使用说明书
上传时间： 2013-10-13
上传用户：brain kung
汇编器在微处理器的验证和应用中举足轻重，如何设计通用的汇编器一直是研究的热点之一。本文提出了一种开放式的汇编器系统设计思想，在汇编语言与机器语言间插入中间代码CMDL（code mapping description language）语言，打破汇编语言与机器语言的直接映射关系，由此建立起一套描述汇编语言与机器语言的开放式映射体系。基于此开放式映射体系开发了一套汇编器系统，具有较高层次上的通用性和可移植性。【关键词】指令集，CMDL，汇编器，开放式 Design of Retargetable Assembler System Liu Ling Feng Wen Nan Wang Ying Chun Jiang An Ping Ji Li Jiu IME of Peking University, 100871【摘要】An assembler plays a very IMPortant role in the field of microprocessor verifications and applications, thus how to build a retargetable assembler system has been a hotspot in this field for long time. This paper presents a new method about the retargetable assembler system design.It provides a kind of language CMDL, code mapping description language. During the process of assembling, assembler languages are firstly translated to CMDL, and then mapped to the machine codes. In an other word, CMDL is inserted between assembler languages and machine codes during the translation procedure. As a medium code, CMDL has a lot of features, such as high extraction, strong descript capabilities. It can describe almost all attributes of assembler languages. By breaking the direct mapping relationship between assembler languages and machine codes, the complexities of machine codes are hided to the users, therefore, the new retargetable assembler system has higher retargetable level by converting the mapping from assembler languages and machine codes to assembler languages and CMDL, and implementationof it becomes easier. Based on the new mapping system structure, a retargetable assemblersystem is developed. It proved the whole system has good retargetability and implantability.【关键词】instruction set, symbol table, assembler, lexical analysis, retargetability
上传时间： 2013-10-10
上传用户：meiguiweishi
基于LabVIEW和单片机的空调温度场测量系统的研究:室内温度是空调系统舒适性的重要指标,对其及时、准确地测量显得非常重要。介绍单片机AT89C51 和数字式、单总线型温度传感器DS18B20 组成矩形测量网络采集空调室内40 点温度,LabVIEW作为开发平台,二者之间通过串口实现数据通信,利用LabVIEW强大的数据处理和显示功能对采集的空调温度场数据进行实时处理、分析和显示,详细介绍了系统的硬件结构和软件模块的设计方案。关键词:单片机;DS18B20 ;LabVIEW;串行通信 Abstract : Temperature is a very IMPortant criterion of air condition system′s comfort , so it is very significant to measure it accurately and real timely. This paper int roduces a data acquisition system of measuring 40 point s temperature for air condition room based on single wire digital sensor DS18B20 and microcont roller AT89C51 which are composed of rectangle measuring meshwork. The data communication between LabVIEW and microcont roller is executed via serial port ,and the temperature field data of air condition room are processed analyzed and displayed on LabVIEW. The hardware and software modules are also given in detail.Keywords : single chip ;DS18B20 ;LabVIEW; serial communication
上传时间： 2014-05-05
上传用户：KSLYZ
