In a recent discussion with a system designer, the requirementfor his power supply was to regulate 1.5Vand deliver up to 40A of current to a load that consistedof four FPGAs. This is up to 60W of power that must bedelivered in a small area with the lowest height profi lepossible to allow a steady fl ow of air for cooling. Thepower supply had to be surface mountable and operateat high enough effi ciency to minimize heat dissipation.He also demanded the simplest possible solution so histime could be dedicated to the more complex tasks. Asidefrom precise electrical performance, this solution had toremovethe heat generated during DC to DC conversionquickly so that the circuit and the ICs in the vicinity do notoverheat. Such a solution requires an innovative designto meet these criteria:
上傳時間： 2013-11-24
上傳用戶：defghi010
In August of 1992 LTC published Application Note 49, “Illumination Circuitry for Liquid Crystal Displays.” One notable aspect of this event is that it generated more response than all previous LTC application notes combined. This level of interest, along with significant performance advances since AN-49’s appearance, justifies further discussion of LCD backlighting circuitry.
上傳時間： 2013-11-19
上傳用戶：lanjisu111
為了提高PCB板制作的效率，改變傳統(tǒng)的化學腐蝕制板工藝，使用機械仿形銑制作電路板的方法，設(shè)計了以ATMEGA16單片機為核心部件的PCB板雕刻機控制系統(tǒng)。其中包括PCB雕刻機的基本功能、主要硬件電路設(shè)計和軟件的實現(xiàn)流程，并給出了相關(guān)設(shè)計電路。重點分析了雕刻機步進電機的驅(qū)動電路以及主軸電機的驅(qū)動電路，該雕刻機經(jīng)實際運行，系統(tǒng)工作良好，可有效提高PCB板的制作效率。 Abstract: In order to improve the efficiency of production of PCB board and change the traditional chemical etching plates， using of mechanical copying milling method makes circuit boards，this paper introduces the PCB engraving machine control system used ATMEGA16 microcomputer as the core components. It includes basic function， the hardware circuit design and software realization process， and gives the corresponding circuit design.It analyses the drive circuit of engrawing machine stepper motor and spindle motor in detail. This engraving machine by practical operation， the system works well， which can effectively improve the production efficiency of PCB board.
上傳時間： 2013-10-17
上傳用戶：liangliang123
便攜式信號采集在機器健康診斷系統(tǒng)中有較高的應(yīng)用價值。機器健康診斷的信號特點是包括低頻信號。本文研究是為了實現(xiàn)簡易而且低成本的低頻便攜式信號采集。以Microchip公司單片機PIC18F1320為核心設(shè)計信號采集電路，實現(xiàn)了信號的采集和保存。系統(tǒng)采用串行電可擦除芯片24LC32A保存數(shù)據(jù)，經(jīng)過有線通信，信號數(shù)據(jù)由串行口通過MAX232芯片輸送到微型計算機接收和保存，最后繪制出信號波形。 微型計算機程序采用Visual Basic編程。研究成功采樣頻率為3 kHz的復(fù)雜信號，證明該方案符合設(shè)計要求。 Abstract: Portable signal acquisition is useful in machine health monitoring systems. The signal characteristics of machine health monitoring includes low frequency signals. The goal of this study is to realize simple, inexpensive and portable low frequency signal sampling. This paper provides the project of signal acquisition system design based on PIC18F1320 microcontroller manufactured by the Microchip Technology Incorporation to achieve signal sampling and storage. The system adopted EEPROM 24LC32A to store the signal data. The microcomputer received data via wired link with the MAX232 IC through the serial port. The microcomputer program, programmed in Visual Basic, received the data, stored it and plotted the signal. The study successfully samples 3kHz complicated signals and thus meets the design requirement.
上傳時間： 2013-11-19
上傳用戶：moerwang
介紹了當前普通標記機控制系統(tǒng)現(xiàn)狀及其存在缺點，給出氣動標記機及相頻修正PWM模式的工作原理。采用ATmega16單片機和USB轉(zhuǎn)換RS232接口器件CH341T實現(xiàn)驅(qū)動控制系統(tǒng)與PC的實時通訊，標記控制系統(tǒng)可升級到USB接口。采用基于ATmega16的相頻修正PWM替換555振蕩電路產(chǎn)生的PWM，可直接通過軟件調(diào)整PWM信號。使用達林頓三極管TIP122替代直流繼電器驅(qū)動高頻電磁閥，使得電磁閥驅(qū)動電路簡單，成本低廉。該控制系統(tǒng)已成功應(yīng)用于氣動標記機。 Abstract: In this paper,the actuality and demerit of the common gas marking machine control systems are described.The operation principle of the gas marking machine and the phase and frequency correct PWM of ATmega16is introduced.The real-time communication between the driving control system and PC by CH341T which its function is translated USB to RS232is realized,the control systems is updated grade to USB interface.The PWM signal can be adjustable by software for the555surge circuit was substituted by the phase and frequency.The high frequency electromagnetic value’s driving circuit by DC relay is replaced by TIP122,therefore,the circuit is become simple and the cost cheap.The control systems has been widely used in gas marking machine.
標簽： ATmega 16 標記 控制系統(tǒng)
上傳時間： 2013-10-18
上傳用戶：1427796291
闡述了一個由上位PC機和AT89C52下位單片機組成的主從分布式溫度巡回檢測系統(tǒng)。主從機采用RS-485 串行通訊標準進行通信，可在下位單片機實現(xiàn)基本的溫度數(shù)據(jù)巡回檢測基礎(chǔ)上，由上位PC機實現(xiàn)綜合處理功能或擴展為遠程操作。整個系統(tǒng)具有巡檢速度快，擴展性好的特點。 Abstract: In this paper,a top PC and AT89C52 under-bit microcontrollers from the main component of the tour distributed temperature detection system is presented. Master and slave can use RS-485 serial communication standards for communications.Based on next-bit machine for basic goods temperature detected data Tour, the top can achieve the integrated treatment of PC functions or for the expansion of long-distance operation. The entire inspection system is fast, expansion.
上傳時間： 2013-10-13
上傳用戶：zhoujunzhen
對于傳統(tǒng)的跑步機無法聯(lián)機組網(wǎng)，保存歷史數(shù)據(jù)，實時調(diào)試等問題，介紹了一個由多臺跑步機通過RS-232串行總線與上位機相連組成的跑步機聯(lián)網(wǎng)系統(tǒng)。系統(tǒng)采用W77E58作為下位機核心控制器件，它具有雙串行通訊端口，其中一個串口用于與變頻器通訊，另一個串口則與上位機相連，構(gòu)成跑步機網(wǎng)絡(luò)。 Abstract: The traditional running machine can not be connected to a network, saving historical data, real time debug etc.In this paper,a new network system which is composed of running machines connected by a RS-232 communication bus is introduced.In the system,W77E58 is used as a core control unit.W77E58 has two serial ports,one is connected to the inverter and the other is connected to the PC. Thus a network appears.
標簽： W77E58 跑步機 聯(lián)網(wǎng)系統(tǒng)
上傳時間： 2014-12-27
上傳用戶：哇哇哇哇哇
針對材料試驗機等設(shè)備中要求測量或控制材料拉伸或壓縮的位移，一般采用光電軸角編碼器檢測位置信號，輸出正交編碼脈沖信號。若采用其他方法檢測位置信號，必然導(dǎo)致電路設(shè)計復(fù)雜，可靠性降低。因此，提出一種基于LS7266R1的電子式萬能材料試驗機設(shè)計方案。給出了試驗機中的控制器工作原理，LS7266R1與單片機的接口硬件設(shè)計，以及主程序軟件流程圖。巧妙地把力量傳感器，位移傳感器等機械運動狀態(tài)的壓力或拉力以及位置坐標，變成了電壓信號和電脈沖數(shù)字信號，供A/D測量和LS7266R1計數(shù)，從而實現(xiàn)了獨立完成材料試驗控制或通過PC機串口命令完成材料試驗控制。 Abstract: Aiming at the requirement that the displacement of the tension and compression always be tested and controlled in the equipement such as material testing machine. The position signal was tested by photoelectric axial angle coder. Therefore， the paper proposes the design of electronic universal testing machine design based on LS7266R1. If the position signal detected by other methods， will inevitably lead to the circuit design complexity， reliability decreased. The work theory of the controller， the hardware interface design between LS7266R1 and single chip， and the flow chart of main program， are presented in this paper. The signal of the compression or tension power and displacement at working， which tested by power sensor and displacement sensor especially， is changed into electric voltage and electric pulse numerical signals. And these signals can be tested by A/D and counted by LS7266R1. Finally the test of the material properties can be controlled by itself， or controlled by the COM command of PC.
上傳時間： 2013-11-02
上傳用戶：yl1140vista
針對當前安檢力學試驗機所能完成的試驗種類單一、自動化程度低等問題，提出一種以ATmega128單片機為核心控制器的安檢力學試驗機的設(shè)計。詳細闡述了該安檢力學試驗機各個組成部分的設(shè)計原理和方案，并且給出了各部分的軟件設(shè)計思想和操作流程。經(jīng)過大量測試試驗表明：設(shè)計的安檢力學試驗機可以完成多達十余種的力學安檢試驗，完全符合相關(guān)國家標準，并且具有數(shù)據(jù)采集精度高、傳輸速度快、操作安全簡便等特點，實現(xiàn)了安檢設(shè)備的多功能化、數(shù)字化和自動化。 Abstract: Currently， many mechanical security testing machines have only one function. The degree of automation of them is low. To solve those problems， a new kind of mechanical security testing machine， using ATmega128 micro-controller as its core controller， has been advanced. It describes the components of the machine. The principles and the scheme in the designing processes are presented in detail， and the software architecture and the operation processes of each part are given. After having done many testing， we have reached the following conclusions: the mechanical security testing machine presented can do over ten mechanical security tests complying with related national standards. It has high data acquisition accuracy and high transmission speed. The operation of the machine is simple and safe. In general， this machine is a multi-functional， highly automatic， digitalized security testing device.
上傳時間： 2013-11-05
上傳用戶：a67818601
Features• Complete DTMF Receiver• Low power consumption• Internal gain setting amplifier• Adjustable guard time• Central office quality• Power-down mode• Inhibit mode• Backward compatible withMT8870C/MT8870C-1Applications• Receiver system for British Telecom (BT) orCEPT Spec (MT8870D-1)• Paging systems• Repeater systems/mobile radio• Credit card systems• Remote control• Personal computers• Telephone answering machine
上傳時間： 2013-11-20
上傳用戶：mpquest
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