A recent trend in the design of portable devices has beento use ceramic capacitors to filter DC/DC Converter inputs.Ceramic capacitors are often chosen because of theirsmall size, low equivalent series resistance (ESR) and highRMS current capability. Also, recently, designers havebeen looking to ceramic capacitors due to shortages oftantalum capacitors.
Switching regulators are of universal interest. LinearTechnology has made a major effort to address this topic.A catalog of circuits has been compiled so that a designengineer can swiftly determine which Converter type isbest. This catalog serves as a visual index to be browsedthrough for a specific or general interest.
The design of battery-powered equipment can often bequite challenging. Since few ICs can operate directly fromthe end-of-life voltage from a 2-cell battery (about 1.8V),most systems require a DC/DCConverter. The systemdesigner often has a limited area in which to place the DC/DC Converter; associated inductors and capacitors must be
光伏發(fā)電是未來新能源發(fā)電重要方向之一，而光伏變流器是光伏發(fā)電系統(tǒng)的核心。介紹一種基于微網(wǎng)理念的光伏變流器設(shè)計。以該變流器為核心的光伏發(fā)電系統(tǒng)可以看做一個小型的微網(wǎng)系統(tǒng)。該系統(tǒng)能根據(jù)外部電網(wǎng)情況，工作于并網(wǎng)模式和離網(wǎng)模式。介紹了該系統(tǒng)的各個組成部件的設(shè)計以及變流器主電路部分器件的選型。最后，由實驗樣機進(jìn)行測試。試驗結(jié)果驗證了電路拓?fù)浣Y(jié)構(gòu)及控制方案的可行性，也說明了系統(tǒng)參數(shù)設(shè)計方法的正確性。
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
The latest generation of Texas Instruments (TI) boardmountedpower modules utilizes a pin interconnect technologythat improves surface-mount manufacturability.These modules are produced as a double-sided surfacemount(DSSMT) subassembly, yielding a case-less constructionwith subcomponents located on both sides of theprinted circuit board (PCB). Products produced in theDSSMT outline use the latest high-efficiency topologiesand magnetic-component packaging. This providescustomers with a high-efficiency, ready-to-use switchingpower module in a compact, space-saving package. Bothnonisolated point-of-load (POL) switching regulators andthe isolated dc/dc Converter modules are being producedin the DSSMT outline.TI’s plug-in power product line offers power modules inboth through-hole and surface-mount packages. The surfacemountmodules produced in the DSSMT outline use asolid copper interconnect with an integral solder ball fortheir
利用單片機具有的智能程序控制的特點，設(shè)計了基于STC89C52單片機的"二極管特性測試器"，可對二極管一般特性進(jìn)行快速測試。通過穩(wěn)定線性電流源給二極管加載恒定電流，然后由高精度模數(shù)轉(zhuǎn)換器測試其壓降，以此為基礎(chǔ)可判斷二極管好壞、檢測二極管極性和測試二極管伏安特性等，避免了用萬用表測試只能測得極性而不知其特性這一缺點。可用于電子設(shè)計制作過程中對二極管進(jìn)行快速測試，以確定被測二極管是否滿足電路的設(shè)計要求。
Abstract:
By making good use of the intelligent control function of the Micro Controller Unit (MCU)， the diode trait tester was designed based on the STC89C52，which could be used to test the trait of a diode rapidly. By loading constant current to diode through the stable linear current source， and measuring the voltage drop of the diode by high-precision analogue-to-digital Converter (ADC)， it can judge whether the diode is good or not， distinguish the polarity of the diode， and test the trait that the diode， which can avoid the fault of using a multimeter can only measure the polarity but not the trait. This device can be used to test the trait of a diode quickly，and to make sure that whether a diode can be used in the electronic design or not.
針對科研實驗中對拉壓千斤頂加載過程控制的需要，采用ATmega128單片機控制步進(jìn)電機進(jìn)而實現(xiàn)對執(zhí)行系統(tǒng)的電動泵站實行自動控制。對力和位移的數(shù)據(jù)采集與處理及用步進(jìn)電機控制電動泵站手柄的技術(shù)細(xì)節(jié)作了重點描述。通過單片機的A/D變換器對AMP放大模塊采集的電橋信號作量化處理，千斤頂?shù)牟倏厥直恢靡离妱佑捅瞄y門開啟的方向和大小作若干定位，單片機根據(jù)力或位移傳感器信號，實時控制步進(jìn)電機驅(qū)動手柄旋轉(zhuǎn)到相應(yīng)操控位置。
Abstract:
This article describes the use of ATmega128 AVR microcontroller series of DBS electric pumping stations and QF100/200 separate twoway hydraulic jack to automate the process of manipulating the work of the technical content. Articles on force and displacement data acquisition and processing， and stepper motor control electric pump with the handle of the key technical details were described. Through the MCU’s A / D Converter module is collected on the AMP amplification quantify the signal bridge， jack handle position control valve opening according to the direction of electric pumps for a number of positioning and size of the microcontroller based on force or displacement sensor signals， real-time control stepper motor drive control handle rotate to the appropriate location.
設(shè)計了一種基于PIC16C71單片機的數(shù)字水溫配制閥。該配制閥采用NTC熱敏電阻作溫度傳感器，與固定電阻組成簡單分壓電路作為水溫測量電路，利用PIC16C71單片機內(nèi)置的8位A/D轉(zhuǎn)換器把熱敏電阻上的模擬電壓轉(zhuǎn)換為數(shù)字量，PIC16C71單片機控制直流電機驅(qū)動混水閥調(diào)節(jié)冷熱水的混合比例實現(xiàn)水溫調(diào)節(jié)。給出了控制電路圖，對水溫測量電路的參數(shù)選擇和測溫精度作了詳細(xì)討論。實驗和分析表明，選用阻值較大的NTC熱敏電阻和分壓電阻可較好地解決熱敏電阻因功耗較大造成的熱擊穿問題。
Abstract:
A digital valve for controlling water temperature based on PIC16C71 was presented in this paper.A bleeder circuit which consisted of a NTC thermistor as temperature sensor and a fixed resistance was designed as water temperature measuring circuit.The analog voltage on the thermistor was converted into digital signal by a 8-bit A/D Converter embedded in PIC16C71. Based on the digital signal， the MCU PIC16C71 drived the valve by a DC motor to adjust the water temperature through adjusting the proportion of hot water and cold water.The circuit diagram of controller was given，the principle，the component parameters and the accuracy of measuring temperatures were also dissertated in detail. It was found by experiment and analysis that thermal breakdown of thermistor caused by high power could be solved by selecting thermistor and fixed resistance with high impedance value.
針對目前使用的RS232接口數(shù)字化B超鍵盤存在PC主機啟動時不能設(shè)置BIOS，提出一種PS2鍵盤的設(shè)計方法。基于W78E052D單片機，采用8通道串行A/D轉(zhuǎn)換器設(shè)計了8個TGC電位器信息采集電路，電位器位置信息以鍵盤掃描碼序列形式發(fā)送，正交編碼器信號通過XC9536XL轉(zhuǎn)換為單片機可接收的中斷信號，軟件接收到中斷信息后等效處理成按鍵。結(jié)果表明，在滿足開機可設(shè)置BIOS同時，又可實現(xiàn)超聲特有功能，不需要專門設(shè)計驅(qū)動程序，接口簡單，成本低。
Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot， this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller，designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D Converter， potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU， software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot， ultrasound specific functionality can be achieved at the same time， it does not require specially designed driver，the interface is simple and low cost.
為提高電容測量精度，針對電容式傳感器的工作原理設(shè)計了基于PIC16LF874單片機電容測量模塊。簡單闡述了電容測量電路的應(yīng)用背景和國內(nèi)外研究現(xiàn)狀，介紹了美國Microchip公司PIC16LF874單片機的特性。電容式傳感器輸出的動態(tài)微弱電容信號通過PS021型電容數(shù)字轉(zhuǎn)換器把模擬量數(shù)據(jù)轉(zhuǎn)換成數(shù)字量數(shù)據(jù)，所測數(shù)據(jù)由PIC16LF874單片機應(yīng)用程序進(jìn)行處理、顯示和保存。實驗結(jié)果表明，固定電容標(biāo)稱值為10~20 pF 的測量值相對誤差在1%以內(nèi)，同時也可知被測電容容值越大，測量值和標(biāo)稱值相對誤差越小。
Abstract:
To improve the accuracy of capacitance measurement，aimed at the principle of work of mercury capacitance acceleration transducer，the design of micro capacitance measurement circuit is based on the key PIC16LF874 chip. Briefly discusses the application of the capacitance measuring circuit for the background and status of foreign researchers，focusing on the United States PIC16LF874 microcontroller features. Capacitive sensor outputed signal through the dynamics of weak PS021-chip capacitors （capacitancedigital Converter） to convert analog data into digital data，the measured data from the PIC16LF874 microcontroller application process， display and preservation. Experimental results show that the fixed capacitor 10pF ~ 20pF nominal value of the measured value of relative error is within 1%，but also it canbe seen the value of the measured capacitance larger，measuring value and the nominal value of relative error smaller.
