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.
High voltage buck DC/DC controllers such as the LTC3890(dual output) and LTC3891 (single output) are popular inautomotive applications due to their extremely wide 4V to60V input voltage range, eliminating the need for a snubberand voltage suppression circuitry. These controllersare also well suited for 48V telecom applications whereno galvanic isolation is required.
Occasionally, we are tasked with designing circuitry for aspecific purpose. The request may have customer originsor it may be an in-house requirement. Alternately, a circuitmay be developed because its possibility is simply tooattractive to ignore1. Over time, these circuits accumulate,encompassing a wide and useful body of proven capabilities.They also represent substantial effort. These considerationsmake publication an almost obligatory propositionand, as such, a group of circuits is presented here. This isnot the first time we have displayed such wares and, giventhe encouraging reader response, it will not be the last2.Eighteen circuits are included in this latest effort, roughlyarranged in the categories given in this publication’s title.They appear at the next paragraph.
數(shù)字控制的交流調(diào)速系統(tǒng)所選用的微處理器、功率器件及產(chǎn)生PWM波的方法是影響交流調(diào)速系統(tǒng)性能好壞的直接因素。在介紹了正弦脈寬調(diào)制(SPWM)技術(shù)的基礎(chǔ)上，設(shè)計了一種以8098單片機作為控制器，以智能功率模塊IPM為開關(guān)器件的變頻調(diào)速系統(tǒng)。通過軟件編程，產(chǎn)生正弦脈沖寬度調(diào)制波形來控制絕緣柵雙極晶體管的導通和關(guān)斷，從而達到控制異步電動機轉(zhuǎn)速的目的。實驗結(jié)果表明，該系統(tǒng)可調(diào)頻率調(diào)電壓，穩(wěn)定度高，調(diào)速范圍寬，具有較強的實用價值
Abstract:
AC variable speed with digital control systems used microprocessors， power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage， high stability， wide speed range， has a strong practical value.
介紹了一種TI公司最新推出的MSP430F247單片機，利用它自帶的I2C模塊驅(qū)動I2C總線的溫度傳感器TMP275。TMP275是一款具有高精度、低功耗的新型溫度傳感器。由于TMP275具有可編程功能，纖小的封裝以及極大的溫度范圍，因而廣泛應用于組建超小型溫度測量裝置。
Abstract:
A new single chip microcomputer MSP430F247 which is released by TI is introduced.It can drive I2C interface digital temperature sensor TMP275 with I2C module.TMP275 is a new temperature sensor which has high accurate,low power. Because TMP275 has programmable function,small packages and wide temperature range,it is applied widely in very little temperature measurment equipment.
針對目前采用的熱敏電阻測量方法，提出了采用單總線數(shù)字式溫度傳感器DS18B20和單片機組成的新型溫度測量儀。介紹DS18B20的結(jié)構(gòu)和工作原理，以及單總線工作原理，給出了由Mega8單片機和DS18B20構(gòu)成的單總線溫度測量儀的硬件電路及軟件流程圖。經(jīng)試驗基于單總線器件DS18B20的溫度測量儀，具有測量準確、測溫范圍寬、體積小、控制方便等優(yōu)點。
Abstract:
This paper brings forward a new temperature meter composed of 1-Wire temperature sensor DS18B20 and MCU which has advantage of the thermistor. In the article, the DS18B20＇s structure and controlling principles are introduced and hardware circuit and software diagram of the temperature meter are given.After been tested,the temperature meter has the advantages of accurate measurement, wide temperature range, small volume and convenient controlling.
基于幅移鍵控技術(shù)ASK（Amplitude-Shift Keying），以C8051F340單片機作為監(jiān)測終端控制器，C8051F330D單片機作為探測節(jié)點控制器，采用半雙工的通信方式，通過監(jiān)控終端和探測節(jié)點的無線收發(fā)電路，實現(xiàn)數(shù)據(jù)的雙向無線傳輸。收發(fā)電路采用直徑為0.8 mm的漆包線自行繞制成圓形空心線圈天線，天線直徑為（3.4±0.3）cm。試驗表明，探測節(jié)點與監(jiān)測終端的通信距離為24 cm，通過橋接方式，節(jié)點收發(fā)功率為102 mW時，節(jié)點間的通信距離可達20 cm。與傳統(tǒng)無線收發(fā)模塊相比，該無線收發(fā)電路在受體積、功耗、成本限制的場合有廣闊的應用前景。
Abstract:
Based on ASK technology and with the C8051F340 and C8051F330D MCU as the controller， using half-duplex communication mode， this paper achieves bi-directional data transfer. Transceiver circuit constituted by enameled wire which diameter is 0.8mm and wound into a diameter （3.4±0.3） cm circular hollow coil antenna. Tests show that the communication distance between detection and monitoring of the terminal is 24cm，the distance is up to 20cm between two nodes when using the manner of bridging and the node transceiver power is 102mW. Compared with the conventional wireless transceiver modules， the circuit has wide application prospect in small size， low cost and low power consumption and other characteristics.
為解決輸油管道溫度壓力參數(shù)實時監(jiān)測的問題，設(shè)計了以C8051F930單片機作為控制核心的超低功耗輸油管道溫度壓力遠程監(jiān)測系統(tǒng)?，F(xiàn)場儀表使用高精度電橋采集數(shù)據(jù)，通過433 MHz短距離無線通信網(wǎng)絡與遠程終端RTU進行通信，RTU通過GPRS網(wǎng)絡與PC上位機進行遠程數(shù)據(jù)傳輸，在上位機中實現(xiàn)數(shù)據(jù)存儲和圖形化界面顯示，從而實現(xiàn)輸油管道溫度壓力參數(shù)的實時監(jiān)測和異常報警。經(jīng)實驗證明，該系統(tǒng)的12位數(shù)據(jù)采集精度滿足設(shè)計要求，漏碼率小于1%，正常工作時間超過5個月，能實時有效地監(jiān)測輸油管道的溫度壓力參數(shù)，節(jié)省大量人工成本，有效預防管道參數(shù)異常造成的經(jīng)濟損失和環(huán)境污染。
Abstract:
In order to solve the problems on real-time monitoring of pipeline temperature and pressure parameters， the ultra-low power remote pipeline temperature and pressure monitoring system was designed by using the single chip processor C8051F930 as the control core. The high-precision electric bridge was used in field instruments for data collection， the 433MHz short-range wireless communication network was used to make communication between field instrument and RTU， the GPRS was used by the RTU to transmit data to the PC host computer， and the data was stored and displayed in the PC host computer， so the real-time monitoring and exception alerts of pipeline temperature and pressure parameters were achieved. The experiment proves that the system of which error rate is less than 1% over five months working with the 12-bit data acquisition accuracy can effectively monitor the pipeline temperature and pressure parameters in real time， it saves a lot of labor costs and effectively prevents environmental pollution and economic losses caused by abnormal channel parameters.
為了在工業(yè)生產(chǎn)及過程控制中準確測量溫度，設(shè)計了一種基于低功耗MSP430單片機的數(shù)字溫度計。整個系統(tǒng)通過單片機MSP430F1121A控制DS18B20讀取溫度，采用數(shù)碼管顯示，溫度傳感器DS18B20與單片機之間通過串口進行數(shù)據(jù)傳輸。MSP430系列單片機具有超低功耗，且外圍的整合性高，DS18B20只需一個端口即可實現(xiàn)數(shù)據(jù)通信，連接方便。通過多次實驗證明，該系統(tǒng)的測試結(jié)果與實際環(huán)境溫度一致，除了具有接口電路簡單、測量精度高、誤差小、可靠性高等特點外，其低成本、低功耗的特點使其擁有更廣闊的應用前景。
Abstract:
In order to obtain accurate measuring temperature in industrial production and process control， a digital thermometer based on MSP430 MCU is designed. The system uses MSP430F1121A MCU to control DS18B20， and gets the temperature data， which is displayed on the LED. The temperature sensor DS18B20 and MCU transmit data through serial communication. MSP430 series has ultra-low power and high integration， DS18B20 only needs one port to achieve data communication. Through many experimental results prove， this system is consistent with actual environment temperature. The system has characteristics of interface circuit simple， high measuring accuracy， minor error， high reliability， besides， the characteristics of low cost and low power make it having vaster application prospect.
The SN65LBC170 and SN75LBC170 aremonolithic integrated circuits designed forbidirectional data communication on multipointbus-transmission lines. Potential applicationsinclude serial or parallel data transmission, cabledperipheral buses with twin axial, ribbon, ortwisted-pair cabling. These devices are suitablefor FAST-20 SCSI and can transmit or receivedata pulses as short as 25 ns, with skew lessthan 3 ns.These devices combine three 3-state differentialline drivers and three differential input linereceivers, all of which operate from a single 5-Vpower supply.The driver differential outputs and the receiverdifferential inputs are connected internally to formthree differential input/output (I/O) bus ports thatare designed to offer minimum loading to the buswhenever the driver is disabled or VCC = 0. Theseports feature a wide common-mode voltage rangemaking the device suitable for party-lineapplications over long cable runs.
