Abstract: Investment in smart meters and smart grid end equipment continues to grow worldwide as countriestry to make their electric delivery systems more efficient. However, as critical as the electric deliveryinfrastructure is, it is normally not secured and thus subject to attack. This article describes the concept oflife-cycle security—the idea that embedded equipment in the smart grid must have security designed into theentire life of the product, even back to the contract manufacturer. We also talk about how life-cycle securityapplies to embedded equipment in the smart grid. Potential threats are discussed, as are potential solutionsto mitigate the risks posed by those threats.
標(biāo)簽： 智能電表 智能電網(wǎng)
上傳時間： 2014-12-24
上傳用戶：熊少鋒
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)
上傳時間： 2013-10-31
上傳用戶：caiguoqing
Abstract: Field-programmable gate arrays (FPGAs) are used in a wide variety of applications and end markets, including digital signalprocessing, medical imaging, and high-performance computing. This application note outlines the issues related to powering FPGAs.It also discusses Maxim's solutions for powering Altera® FPGAs.
上傳時間： 2013-11-02
上傳用戶：zhaoman32
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.
上傳時間： 2013-11-23
上傳用戶：lu2767
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
上傳時間： 2014-12-24
上傳用戶：569342831
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
上傳時間： 2013-11-04
上傳用戶：wfl_yy
Each year Vishay releases thousands of new components that enable our customers to create new and superior end products. We recognize that offering unique component solutions helps improve the performance of next-generation devices, overcome technical barriers, and create new markets.
上傳時間： 2013-12-14
上傳用戶：ming529
For a variety of reasons, it is desirable to charge batteriesas rapidly as possible. At the same time, overchargingmust be limited to prolong battery life. Such limitation ofovercharging depends on factors such as the choice ofcharge termination technique and the use of multi-rate/multi-stage charging schemes. The majority of batterycharger ICs available today lock the user into one fixedcharging regimen, with at best a limited number ofcustomization options to suit a variety of application needsor battery types. The LTC®1325 addresses these shortcomingsby providing the user with all the functionalblocks needed to implement a simple but highly flexiblebattery charger (see Figure 1) which not only addressesthe issue of charging batteries but also those of batteryconditioning and capacity monitoring.
上傳時間： 2013-10-19
上傳用戶：royzhangsz
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
上傳時間： 2013-11-23
上傳用戶：wys0120
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
上傳時間： 2013-10-30
上傳用戶：hz07104032
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