As the performance of many handheld devices approachesthat of laptop computers, design complexity also increases.Chief among them is thermal management—how doyou meet increasing performance demands while keepinga compact and small product cool in the user’s hand?For instance, as battery capacities inevitably increase,charge currents will also increase to maintain or improvetheir charge times. Traditional linear regulator-based batterychargers will not be able to meet the charge currentand effi ciency demands necessary to allow a product torun cool. What is needed is a switching-based chargerthat takes just about the same amount of space as a linearsolution—but without the heat.
上传时间： 2013-11-23
上传用户：lu2767
Speed and accuracy don’t always go hand-in-handin DC/DC converter systems—that is, until now. TheLTC3811 is a dual output, fi xed frequency current modeDC/DC switching regulator controller designed for one oftoday’s most demanding power supply applications: highcurrent, low voltage processor core supplies.
上传时间： 2013-11-21
上传用户：aix008
Today’s computer, datacom, and telecom systems demandpower supplies that are effi cient, respond quicklyto load transients and accurately regulate the voltageat the load. For example, load current can be measuredby using the inductor DCR, thus eliminating the needfor a dedicated sense resistor. Inductor DCR sensingincreases effi ciency—especially at heavy load—whilereducing component cost and required board space.The LTC®3856 single-output 2-phase synchronous buckcontroller improves the accuracy of inductor DCR sensingby compensating for changes in DCR due to temperature.
上传时间： 2013-11-05
上传用户：guobing703
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.
上传时间： 2013-10-13
上传用户：dongqiangqiang
Once relegated to the hinterlands of low cost indicatorlights, the LED is again in the spotlight of the lightingworld. LED lighting is now ubiquitous, from car headlightsto USB-powered lava lamps. Car headlights exemplifyapplications that capitalize on the LED’s clear advantages—unwavering high quality light output, tough-assteelrobustness, inherent high effi ciency—while a USBlava lamp exemplifi es applications where only LEDs work.Despite these clear advantages, their requirement forregulated voltage and current make LED driver circuitsmore complex than the venerable light bulb, but some newdevices are closing the gap. For instance, the LTM®8040μModule™ LED driver integrates all the driver circuitryinto a single package, allowing designers to refocus theirtime and effort on the details of lighting design criticalto a product’s success.
上传时间： 2013-10-16
上传用户：togetsomething
交一直一交变频器的中间直流环节如果是用大电容平波通常称为电压源型变频器。如果分开来称呼，则其后端逆变器部分叫电压源逆变器(VSI)，产品GB和IEC标准也是这种称呼。其前端整流部分对电网而言是— 个谐波源，也就叫电压型谐波源。与此相对照，交一直一交变频器的中间直流环节如果用大电感平波就分别称为电流源型变频器、电流源逆变器(CSD、电流源型谐波源。之所以要特别区分变频器为电压源和电流源两大类是因为他们的交流输入电流波形和变频后输出的交流电压和交流电流的波形及性能都有很大的不同。
上传时间： 2013-11-03
上传用户：xitai
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.
上传时间： 2013-11-05
上传用户：coeus
One of the fi rst lessons in a basic electronics coursecovers the symbols for resistors, capacitors, inductors,voltage sources and current sources. Althougheach symbol represents a functional component of areal-world circuit, only some of the symbols have directphysical counterparts. For instance, the three discretepassive devices—resistors, capacitors, inductors—canbe picked off a shelf and placed on a real board muchas their symbolic analogs appear in a basic schematic.Likewise, while voltage sources have no direct 2-terminalanalog, a voltage source can be easily built with an offthe-shelf linear regulator.
上传时间： 2013-11-24
上传用户：simonpeng
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.
上传时间： 2013-11-10
上传用户：diets
In predominantly digital systems it is often necessaryto include linear circuit functions. Traditionally, separatepower supplies have been used to run the linear components(see Box, “Linear Power Supplies—Past, Present,and Future”).
标签： Designing Operation Circuits Linear
上传时间： 2013-11-04
上传用户：sdq_123
