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While simplicity and high effi ciency (for cool running) areno longer optional features in isolated power supplies, itis traditionally diffi cult to achieve both. Achieving higheffi ciency often requires the use of advanced topologiesand home-brewed secondary synchronous rectifi cationschemes once reserved only for higher power applications.This only adds to the parts count and to the designcomplexity associated with the reference and optocouplercircuits typically used to maintain isolation. Fortunately, abreakthrough IC makes it possible to achieve both high efficiency and simplicity in a synchronous fl yback topology.The lt®3825 simplifi es and improves the performance oflow voltage, high current fl yback supplies by providingprecise synchronous rectifi er timing and eliminating theneed for optocoupler feedback while maintaining excellentregulation and superior loop response.
標(biāo)簽：
1011
DN
高效率
隔離型
上傳時(shí)間：
2013-10-16
上傳用戶：wayne595
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Video cable driver amplifi er output stages traditionallyrequire a supply voltage of at least 6V in order to providethe required output swing. This requirement is usuallymet with 5V supplies by adding a boost regulator or asmall local negative rail, say via the popular lt®1983-3.Such additional circuitry is unnecessary in typical 1VP-Pvideo connections, such as HD component video, if thecable driver amplifi ers simply offer near rail-to-rail outputcapability when powered from 5V.
標(biāo)簽：
5V電源
高分辨率
視頻解決
方案
上傳時(shí)間：
2013-11-16
上傳用戶：yanyangtian
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Automotive batteries, industrial power supplies, distributedsupplies and wall transformers are all sources ofwide-ranging high voltage inputs. The easiest way to stepdown these sources is with a high voltage monolithicstep-down regulator that can directly accept a wide inputrange and produce a well-regulated output. The lt®3493accepts inputs from 3.6V to 36V and lt3481 acceptsinputs from 3.6V to 34V. Both provide excellent lineand load regulation and dynamic response. The lt3481offers a high effi ciency solution over a wide load range andkeeps the output ripple low during Burst Mode® operationwhile the lt3493 provides a tiny solution with minimalexternal components. The lt3493 operates at 750kHzand the lt3481 has adjustable frequency from 300kHzto 2.8MHz. High frequency operation enables the use ofsmall, low cost inductors and ceramic capacitors.
標(biāo)簽：
寬
輸入
降壓型穩(wěn)壓器
上傳時(shí)間：
2014-12-24
上傳用戶：Pzj
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Piezoelectric motors are used in digital cameras for autofocus,zooming and optical image stabilization. Theyare relatively small, lightweight and effi cient, but theyalso require a complicated driving scheme. Traditionally,this challenge has been met with the use ofseparatecircuits, including a step-up converter and an oversizedgeneric full-bridge drive IC. The resulting high componentcount and large board space are especially problematicin the design of cameras for ever shrinking cell phones.The lt®3572 solves these problems by combining astep-up regulator and a dual full-bridge driver in a 4mm× 4mm QFN package. Figure 1 shows a typical lt3572Piezo motor drive circuit. A step-up converter is usedto generate 30V from a low voltage power source suchas a Li-Ion battery or any input power source within thepart’s wide input voltage range of 2.7V to 10V. The highoutput voltage of the step-up converter, adjustable upto 40V, is available for the drivers at the VOUT pin. Thedrivers operate in a full-bridge fashion, where the OUTAand OUTB pins are the same polarity as the PWMA andPWMB pins, respectively, and the OUTA and OUTB pinsare inverted from PWMA and PWMB, respectively. Thestep-up converter and both Piezo drivers have their ownshutdown control. Figure 2 shows a typical layout
標(biāo)簽：
436
DN
全橋
壓電
上傳時(shí)間：
2013-11-18
上傳用戶：hulee
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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.
標(biāo)簽：
465
DN
超低功耗
升壓轉(zhuǎn)換器
上傳時(shí)間：
2013-11-23
上傳用戶：新手無憂
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Avalanche photo diode (APD) receiver modules arewidely used in fi ber optic communication systems. AnAPD module contains the APD and a signal conditioningamplifi er, but is not completely self contained. It stillrequires signifi cant support circuitry including a highvoltage, low noise power supply and a precision currentmonitor to indicate the signal strength. The challenge issqueezing this support circuitry into applications withlimited board space. The lt®3482 addresses this challengeby integrating a monolithic DC/DC step-up converter andan accurate current monitor. The lt3482 can supportup to a 90V APD bias voltage, and the current monitorprovides better than 10% accuracy over four decades ofdynamic range (250nA to 2.5mA).
標(biāo)簽：
GPON
APD
方案
上傳時(shí)間：
2014-01-18
上傳用戶：wenyuoo
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As environmental concerns over traditional lighting increaseand the price of LEDs decreases, high power LEDsare fast becoming a popular lighting solution for offl ineapplications. In order to meet the requirements of offl inelighting—such as high power factor, high effi ciency, isolationand TRIAC dimmer compatibility—prior LED driversused many external discrete components, resulting incumbersome solutions. The lt®3799 solves complexity,space and performance problems by integrating all therequired functions for offl ine LED lighting.
標(biāo)簽：
LED
離線式
照明
上傳時(shí)間：
2013-10-13
上傳用戶：dongqiangqiang
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Providing power for the Pentium® microprocessor family isnot a trivial task by any means. In an effort to simplify thistask we have developed a new switching regulator controlcircuit and a new linear regulator to address the needs ofthese processors. Considerable time has been spent developingan optimized decoupling network. Here are severalcircuits using the new ltC®1266 synchronous buck regulatorcontrol chip and the lt®1584 linear regulator toprovide power for Pentium processors and Pentium VREprocessors. The Pentium processor has a supply requirementof 3.3V ±5%. The Pentium VRE processor requires3.500V ±100mV.
標(biāo)簽：
C-VR
54
奔騰
微處理器
上傳時(shí)間：
2013-11-01
上傳用戶：名爵少年
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Portable, battery-powered operation of electronic apparatushas become increasingly desirable. Medical, remotedata acquisition, power monitoring and other applicationsare good candidates for batteryoperation. In some circumstances,due to space, power or reliability considerations,it is preferable to operate the circuitry from a single 1.5Vcell. Unfortunately, a 1.5V supply eliminates almost alllinear ICs as design candidates. In fact, the LM10 opamp-reference and the lt®1017/lt1018 comparators arethe only IC gain blocks fully specifi ed for 1.5V operation.Further complications are presented by the 600mV dropof silicon transistors and diodes. This limitation consumesa substantial portion of available supply range, makingcircuit design diffi cult. Additionally, any circuit designedfor 1.5V operation mustfunction at end-of-life batteryvoltage, typically 1.3V. (See Box Section, “Componentsfor 1.5V Operation.”)
標(biāo)簽：
Circuitry
Operation
Single
Cell
上傳時(shí)間：
2013-10-30
上傳用戶：hz07104032
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MSP430F149學(xué)習(xí)板的word資料，方便直接打印。
標(biāo)簽：
430F
F149
430
149
上傳時(shí)間：
2013-11-09
上傳用戶：ajaxmoon
