Automotive power systems are unforgiving electronicenvironments. Transients to 90V can occur When thenominal voltage range is 10V to 15V (ISO7637), along withbattery reversal in some cases. It’s fairly straightforwardto build automotive electronics around this system, butincreasingly end users want to operate portable electronics,such as GPS systems or music/video players,and to charge their Li-Ion batteries from the automotivebattery. To do so requires a compact, robust, effi cientand easy-to-design charging system
上傳時(shí)間： 2013-11-04
上傳用戶：wfl_yy
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.
標(biāo)簽： 超級(jí)電容器 備用電源 手持設(shè)備
上傳時(shí)間： 2013-11-05
上傳用戶：coeus
Abstract: As electronic systems take over many of the mechanical functions in a car—ranging from engine timing to steering andbraking—there is a growing concern about fault tolerance. There should not be a single point of failure that would prevent a car fromat least "limping" off the road or making it to the nearest service station. Redundant systems, watchdog timers, and other controlcircuits are used to reroute signals and perform other functions that ensure that a vehicle can safely make it off the road When afailure occurs.
標(biāo)簽： 看門狗定時(shí)器 汽車安全系統(tǒng)
上傳時(shí)間： 2013-11-10
上傳用戶：diets
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.
標(biāo)簽： Wide-input modules offer dc
上傳時(shí)間： 2014-12-24
上傳用戶：dragonhaixm
Digitemp Junior – An RS-232 Port-Powered Digital Thermometer Digitemp Jr. is a device that is designed to measure and report ambient temperature. When connected to an RS-232 port on any PC, it will periodically measure and report in ASCII form the ambient temperature in degrees Celsius. These temperature readings can be monitored with any terminal program. If the terminal program supports capture to disk, the temperature readings can be saved to disk for further analysis with a spreadsheet program or other data analysis tool. The simple ASCII output format of Digitemp Jr. makes it rel- atively easy to write custom software for receiving, recording, and analyzing ambient temperature data. Best of all, Digitemp Jr. requires no external power sup- plies or batteries. It is powered directly by the RS-232 port.
標(biāo)簽： Microchip 232 PIC RS
上傳時(shí)間： 2013-10-21
上傳用戶：baitouyu
針對(duì)目前使用的RS232接口數(shù)字化B超鍵盤存在PC主機(jī)啟動(dòng)時(shí)不能設(shè)置BIOS，提出一種PS2鍵盤的設(shè)計(jì)方法。基于W78E052D單片機(jī)，采用8通道串行A/D轉(zhuǎn)換器設(shè)計(jì)了8個(gè)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(hào)通過(guò)XC9536XL轉(zhuǎn)換為單片機(jī)可接收的中斷信號(hào)，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(jī)可設(shè)置BIOS同時(shí)，又可實(shí)現(xiàn)超聲特有功能，不需要專門設(shè)計(jì)驅(qū)動(dòng)程序，接口簡(jiǎn)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.
標(biāo)簽： 單片機(jī) B超 數(shù)字化 鍵盤設(shè)計(jì)
上傳時(shí)間： 2013-10-10
上傳用戶：asdfasdfd
Digitemp Jr. is a device that is designed to measure and report ambient temperature. When connected to an RS-232 port on any PC, it will periodically measure and report in ASCII form the ambient temperature in degrees Celsius. These temperature readings can be monitored with any terminal program. If the terminal program supports capture to disk, the temperature readings can be saved to disk for further analysis with a spreadsheet program or other data analysis tool. The simple ASCII output format of Digitemp Jr. makes it relatively easy to write custom software for receiving, recording, and analyzing ambient temperature data. Best of all, Digitemp Jr. requires no external power supplies or batteries. It is powered directly by the RS-232 port.
上傳時(shí)間： 2013-10-20
上傳用戶：Maple
AVR32801: UC3A3 Schematic Checklist Features • Power circuit • Reset circuit • USB connection • External bus interface • ABDAC sound DAC interface • JTAG and Nexus debug ports • Clocks and crystal oscillators • MMC, SD-card, SDHC, SDIO and CE-ATA interface 1 Introduction A good hardware design comes from a proper schematic. Since UC3A3 devices have a fair number of pins and functions, the schematic for these devices can be large and quite complex. This application note describes a common checklist which should be used When starting and reviewing the schematics for a UC3A3 design.
標(biāo)簽： Schematic 32801 UC3A3 Chec
上傳時(shí)間： 2014-12-26
上傳用戶：DXM35
飛機(jī)電網(wǎng)故障時(shí)，機(jī)載電氣盒必須在延遲時(shí)間內(nèi)切斷電網(wǎng)，保護(hù)機(jī)載設(shè)備。采用AT89S52設(shè)計(jì)的電氣盒測(cè)試儀能夠測(cè)試電氣盒保護(hù)功能，測(cè)量延遲時(shí)間。實(shí)際應(yīng)用結(jié)果表明，該測(cè)試儀具有測(cè)量準(zhǔn)確、可靠性高、成本低等優(yōu)點(diǎn)。 Abstract: The helicopter-electrical-box must shut off the helicopter power，protect the equipments of the helicopter When the helicopter power is failed.The tester for the helicopter-electrical-box based on AT89S52is used for testing the protect-ing function and measuring the delay time.Application results show this tester has some advantages,such as accurate mea-surement,high dependability,economical cost etc.
上傳時(shí)間： 2014-12-27
上傳用戶：786334970
在汽車發(fā)動(dòng)機(jī)起動(dòng)時(shí)，若發(fā)動(dòng)機(jī)起動(dòng)后起動(dòng)機(jī)不能及時(shí)斷電，將會(huì)燒毀起動(dòng)機(jī)或損壞飛輪齒環(huán)；若變速器不在空檔位置起動(dòng)，則起動(dòng)機(jī)的瞬間動(dòng)力將使汽車位移，還可能引起交通事故和人身安全。為此介紹一種利用NXP P89LPC901單片機(jī)控制的汽車起動(dòng)保護(hù)控制器，通過(guò)檢測(cè)汽車起動(dòng)開關(guān)、變速箱檔位、發(fā)動(dòng)機(jī)轉(zhuǎn)速，實(shí)現(xiàn)對(duì)汽車發(fā)動(dòng)機(jī)起動(dòng)過(guò)程檢測(cè)和保護(hù)。起動(dòng)保護(hù)控制器在發(fā)動(dòng)機(jī)起動(dòng)過(guò)程中通過(guò)采用逐個(gè)關(guān)閉打開負(fù)載系統(tǒng)，解決汽車發(fā)動(dòng)機(jī)過(guò)程中因起動(dòng)電流大而對(duì)汽車電源的沖擊影響,延長(zhǎng)了電瓶壽命。 Abstract: When the automotive engine is started, the engine start motor and flywheel gear may be damaged， even traffic accidents and personal safeties may be caused by wrong operation or other factors.In order to ensure the automotive engine can be started normally and safely,it is necessary that the protecting measures and methods are considered in the automotive electrical control system.This paper introduces a kind of the automotive engine starting protect controller based on NXP P89LPC901 MCU.The controller can protect the engine starting process by detecting the starter key switch,transmission stall and engine speed.Through the use of close and open load system,the controller can solve the impact on automotive power because of the high-current load in the process of the automobile engine starting, and extend battery life.
上傳時(shí)間： 2013-10-15
上傳用戶：mikesering
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