基于FPGA的静止图像压缩系统的研究-JPEG编码器的设计电力电子与电力传动数字图像在人们生活中的应用越来越广泛，由于原始图像数据量比较大，因此数字图像压缩技术逐渐成为图像应用的一个核心环节。在数字图像压缩领域，国际标准化组织于1992年推出的JPEG标准应用最为广泛。 本文基于FPGA设计了JPEG图像压缩系统，通过改进算法，优化结构，在合理的利用硬件资源的条件下，有效的挖掘出算法内部的并行性。改进了DCT变换算法，设计了并行查找表结构的乘法器，采用了流水线优化算法来解决时间并行性问题，提高了DCT模块的运算速度。依据Huffman编码表的规律性，采用并行查找表结构，用较少的存储单元完成了Huffman编码运算，同时提高了编码速度。整个设计通过EDA软件进行了逻辑综合及功能与时序仿真。综合和仿真结果表明，本文提出的算法在速度和资源利用方面均达到了较好的状态，可满足实时JPEG图像压缩的要求。 设计了一个硬件开发平台，对JPEG图像压缩系统进行了验证。硬件平台上使用ADV7181B来实现AD转换；使用TI公司TMS320C6416型DSP芯片实现了系统配置以及通过PCI接口与上位机PC的实现数据交换；使用Microsoft VC++6．0开发平台开发了系统控制软件平台，实现对整个压缩系统的控制。
上传时间： 2013-05-24
上传用户：GHF
凌力爾特公司提供了一個規模龐大且不斷成長的高電壓 DC/DC 轉換器繫列，這些器件是專為驅動高功率 LED 而設計的。
上传时间： 2013-11-12
上传用户：playboys0
LTC®3838 是一款双输出、两相降压型控制器，其采用一种受控恒定导通时间、谷值电流模式架构，可提供快速负载阶跃响应、高开关频率和低占空比能力。开关频率范围为 200kHz 至 2MHz，其锁相环可在稳态操作期间保持固定频率，并可同步至一个外部时钟
上传时间： 2013-11-09
上传用户：uuuuuuu
电源芯片
上传时间： 2013-10-12
上传用户：hgy9473
开关电源芯片
上传时间： 2013-11-04
上传用户：aix008
Automobile electronic systems place high demands ontoday’s DC/DC converters. They must be able to preciselyregulate an output voltage in the face of wide temperatureand input voltage ranges—including load dump transientsin excess of 60V and cold crank voltage drops to 4V. Theconverter must also be able to minimize battery drain inalways-on systems by maintaining high effi ciency over abroad load current range. Similar demands are made bymany 48V nonisolated telecom applications, 40V FireWireperipherals and battery-powered applications with autoplug adaptors. The LT3437’s best in classperformancemeets all of these requirements in a small thermallyenhanced 3mm × 3mm DFN package.
上传时间： 2013-10-15
上传用户：stampede
Battery powered applications that have a signifi cantamount of time in standby mode, require electrical circuitsto operate with a low quiescent current to preserve batterylife. The LTC3835 synchronous step-down controlleris an excellent solution with its ultralow quiescent current(80μA). Other features make it uniquely qualifi ed tosatisfy the needs of automotive applications. A wide 4Vto 36V input voltage range protects the supply againsthigh input voltage transients and is compatible with lowvoltage cold crank conditions. The constant frequencycurrent-mode architecture with high-side inductor current
上传时间： 2013-11-20
上传用户：stewart·
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.
上传时间： 2014-12-24
上传用户：Pzj
Many telecommunications and computing applicationsneed high effi ciency step-down DC/DC converters thatcan operate from a very low input voltage. The highoutput power synchronous controller LT3740 is idealfor these applications, converting input supplies rangingfrom 2.2V to 22V to outputs as low as 0.8V with loadcurrents from 2A to 20A. Applications include distributedpower systems, point-of-load regulation and conversionof logic supplies.
上传时间： 2013-11-05
上传用户：zhf01y
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
