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Abstract: A resistive feedback network is often used to set the output voltage of a power supply. A mechanical potentiometer (pot)conveniently solves the problem of adjusting a power supply. For easier automatic calibration, a mechanical pot can be replaced witha digital pot. This application note presents a calibration solution that uses a digital pot, because digipots are smaller, do not movewith age or vibration, and can be recalibrated remotely. This proposed solution reduces the susceptibility of the system to thetolerance of the digital pot's end-to-end resistance, making the solution optimal fordesigners. This application note also explainssome of the equations required to calculate the resistor chain values and to use a digital pot in this way. A spreadsheet withstandard reisistor values is available for easy calculations.
標(biāo)簽：
電源供應(yīng)器
數(shù)字電位器
應(yīng)用筆記
校準(zhǔn)
上傳時(shí)間：
2013-10-31
上傳用戶：caiguoqing
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easy-to-use and compact point-of-load power suppliesare necessary in systems with widely distributed, highcurrent, low voltage loads. The LTC®3415 provides acompact, simple and versatile solution. It includes a pairof integrated complementary power MOSFETs (32mΩtop and 25mΩ bottom) and requires no external senseresistor. A complete design requires an inductor andinput/output capacitors, and that’s it. The result is a fast,constant frequency, 7A current mode DC/DC switchingregulator.
標(biāo)簽：
387
DN
級聯(lián)
負(fù)載
上傳時(shí)間：
2013-10-18
上傳用戶：avensy
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Alkaline batteries are convenient because they’re easy tofi nd and relatively inexpensive, making them the powersource of choice for portable instruments and devicesused for outdoor recreation. Their long shelf life alsomakes them an excellent choice for emergency equipmentthat may see infrequent use but must be ready to go on amoment’s notice. It is important that the DC/DC convertersin portable devices operate over the widest possiblebattery voltage range to extend battery run time, and thussave the user from frequent battery replacement.
標(biāo)簽：
428
DN
同步升壓
轉(zhuǎn)換器
上傳時(shí)間：
2014-12-24
上傳用戶：569342831
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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
標(biāo)簽：
464
USB
DN
高效率
上傳時(shí)間：
2013-11-04
上傳用戶：wfl_yy
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Many system designers need an easy way to producea negative 3.3V power supply. In systems that alreadyhave a transformer, one option is to swap out the existingtransformer with one that has an additional secondarywinding. The problem with this solution is that manysystems now use transformers that are standard, offthe-shelf components, and most designers want toavoid replacing a standard, qualifi ed transformer with acustom version. An easier alternative is to produce thelow negative voltage rail by stepping down an existingnegative rail. For example, if the system already employsan off-the-shelf transformer with two secondary windingsto produce ±12V, and a –3.3V rail is needed, a negativebuck converter can produce the –3.3V output from the–12V rail.
標(biāo)簽：
458
DN
降壓轉(zhuǎn)換器
低電壓
上傳時(shí)間：
2013-10-09
上傳用戶：Jerry_Chow
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The LTM8020, LTM8021, LTM8022 and LTM8023 μModule®regulators are complete easy-to-use encapsulated stepdownDC/DC regulators intended to take the pain and aggravationout of implementing a switching power supplyonto a system board. With a μModule regulator, you onlyneed an input cap, output cap and one or two resistorsto complete the design. As one might imagine, this highlevel of integration greatly simplifi es the task of printedcircuit board design, reducing the effort to four categories:component footprint generation, component placement,routing the nets, and thermal vias.
標(biāo)簽：
DCDC
穩(wěn)壓器
印刷電路板
上傳時(shí)間：
2014-01-18
上傳用戶：laomv123
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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
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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.
標(biāo)簽：
PIC
232
RS
單片機(jī)
上傳時(shí)間：
2013-10-20
上傳用戶：Maple
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提出一種基于凌陽單片機(jī)的步進(jìn)電機(jī)加減速的控制方法。采用凌陽科技推出的16位結(jié)構(gòu)工控單片機(jī)SPMC75F2413A為控制器，由Allegro公司生產(chǎn)的兩相步進(jìn)電機(jī)專用驅(qū)動器件SLA7042M構(gòu)成步進(jìn)電機(jī)的驅(qū)動電路，在傳統(tǒng)的3段直線加減速控制算法基礎(chǔ)上增加至7段S形曲線加減速過程，控制步進(jìn)電機(jī)的啟動和停止。實(shí)驗(yàn)結(jié)果表明，該控制方法克服了直線加減速中不連續(xù)、易造成系統(tǒng)沖擊的問題，整個(gè)系統(tǒng)實(shí)現(xiàn)柔性控制，電機(jī)啟動、停止連續(xù)性能提高30%。
Abstract:
The method of controlled stepping motor is referred based on SPMC75F2413A MCU， which adopts the 16 knots SPMC75F2413A MCU as the controller. The special-purpose actuation chip SLA7042M of two stepping motor produced by Allegro Corporation constituted to actuation electric circuit. The purpose of increasing to seven section of S shape curve based on the traditional three sections of straight line is to control the start and stop process of stepping motor. The experimental results show that the control method solves easy to pull-out and overshot problems. The overall system realizes flexible control， and the performance of motor start or stop continuity is increased 30%
標(biāo)簽：
凌陽單片機(jī)
步進(jìn)電機(jī)
減
控制方法
上傳時(shí)間：
2013-12-08
上傳用戶：jiangfire
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為提高溫度測量效率，降低系統(tǒng)的成本，擴(kuò)展傳輸距離，設(shè)計(jì)出一種新型溫度采集系統(tǒng)。單片機(jī)通過控制具有單總線方式的溫度傳感器DS18B20實(shí)現(xiàn)對溫度的測量，同時(shí)單片機(jī)通過控制具有單總線方式300～450MHz頻率范圍內(nèi)的MAX7044與MAX7033無線發(fā)射與接收芯片實(shí)現(xiàn)溫度數(shù)據(jù)的無線傳輸。與傳統(tǒng)溫度采集系統(tǒng)相比，該系統(tǒng)利用單總線方式連接，采用無線傳輸方式實(shí)現(xiàn)遠(yuǎn)距離通信，易于系統(tǒng)的集成與擴(kuò)展。實(shí)驗(yàn)結(jié)果表明，該系統(tǒng)結(jié)構(gòu)簡單、方便移植，能夠同時(shí)實(shí)現(xiàn)多達(dá)上百點(diǎn)溫度的測量與500m范圍的傳輸。
Abstract:
To improve the temperature measurement efficiency and reduce system cost,expansion of transmission distance,a new type of temperature acquisition system is designed.Microcontroller controlled temperature sensor DS18B20which has a single-bus achieves temperature measurement,while microcontroller by controlled the MAX7044and MAX7033chip with a single-bus and having300~450MHz radiofrequency to achieve the wireless transmission of temperature data.Compared with conventional temperature acquisition system,the system uses single-bus connected,and uses wireless transmission means to achieve long-distance communications,easy-to-system integration and expansion.The experimental results show that the system is simple,convenient transplantation,and can be implemented in as many as a hundred-point temperature measure-ment and the transmission range of500meters.
標(biāo)簽：
單總線
無線溫度
采集
系統(tǒng)設(shè)計(jì)
上傳時(shí)間：
2013-10-29
上傳用戶：515414293
