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.
上傳時間： 2013-10-16
上傳用戶：togetsomething
The LTC®4155 and LTC4156 are dual multiplexed-inputbattery chargers with PowerPath™ control, featuring I2Cprogrammability and USB On-The-Go for systems suchas tablet PCs and other high power density applications.The LTC4155’s float voltage (VFLOAT) range is optimizedfor Li-Ion batteries, while the LTC4156 is optimized forlithium iron phosphate (LiFePO4)batteries, supportingsystem loads to 4A with up to 3.5A of battery chargecurrent. I2C controls a broad range of functions and USBOn-The-Go functionality is controlled directly from theUSB connector ID pin.
上傳時間： 2013-10-09
上傳用戶：hanhanj
High voltage buck DC/DC controllers such as the LTC3890(dual output) and LTC3891 (single output) are popular inautomotive applications due to their extremely wide 4V to60V input voltage range, eliminating the need for a snubberand voltage suppression circuitry. These controllersare also well suited for 48V telecom applications whereno galvanic isolation is required.
上傳時間： 2013-10-31
上傳用戶：wwwe
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.
上傳時間： 2013-11-24
上傳用戶：simonpeng
The voltage range of Linear Technology’s PowerPath® circuitscan be easily extended with just a few components, thusallowing them to meet the needs of virtually all applications.This application note presents solutions for circuits thatmust withstand large negative voltages, a reverse adapterinput for example, and circuits that must withstand largepositive inputs, such as automotive load-dump.
上傳時間： 2013-10-21
上傳用戶：幾何公差
Avalanche photodiodes (APDs) are widely utilized in laserbased fiberoptic systems to convert optical data intoelectrical form. The APD is usually packaged with a signalconditioning amplifier in a small module. An APD receivermodule and attendant circuitry appears in Figure 1. TheAPD module (figure right) contains the APD and a transimpedance(e.g., current-to-voltage) amplifier. An opticalport permits interfacing fiberoptic cable to the APD’sphotosensitive portion. The module’s compact constructionfacilitates a direct, low loss connection between theAPD and the amplifier, necessary because of the extremelyhigh speed data rates involved
上傳時間： 2013-10-25
上傳用戶：brain kung
Telecommunication, satellite links and set-top boxes allrequire tuning a high frequency oscillator. The actualtuning element is a varactor diode, a 2-terminal device thatchanges capacitance as a function of reverse bias voltage.1 The oscillator is part of a frequency synthesizingloop, as detailed in Figure 1. A phase locked loop (PLL)compares a divided down representation of the oscillatorwith a frequency reference. The PLL’s output is levelshifted to provide the high voltage necessary to bias thevaractor, which closes a feedback loop by voltage tuningthe oscillator. This loop forces the voltage controlledoscillator (VCO) to operate at a frequency determined bythe frequency reference and the divider’s division ratio.
上傳時間： 2013-12-20
上傳用戶：ABCDE
Photomultipliers (PMT), avalanche photodiodes (APD),ultrasonic transducers, capacitance microphones, radiationdetectors and similar devices require high voltage,low current bias. Additionally, the high voltage must bepristinely free of noise; well under a millivolt is a commonrequirement with a few hundred microvolts sometimesnecessary. Normally, switching regulator confi gurationscannot achieve this performance level without employingspecial techniques. One aid to achieving low noise is thatload currents rarely exceed 5mA. This freedom permitsoutput fi ltering methods that are usually impractical
上傳時間： 2013-10-28
上傳用戶：lhw888
The LTM4600 DC/DC μModule regulator is a complete highpower density stepdown regulator for 10A continuous (14Apeak) loads. The device has two voltage options: 20VINmaximum for the LTM4600EV and 28VIN maximum for theLTM4600HVEV each housed in a small 15mm ¥ 15mm ¥2.8mm LGA surface mount package.
上傳時間： 2013-10-10
上傳用戶：adada
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
