To this day, Power over Ethernet (PoE) continues to gainpopularity in today’s networking world. The 12.95Wdelivered to the Powered Device (PD) input supplied bythe Power Sourcing Equipment (PSE) is a universal supply.Each PD provides its own DC/DC conversion from anominal 48V supply, thus eliminating the need for a correctvoltage wall adapter. However, higher power devicescan not take advantage of standard PoE because of itspower limitations, and must rely on a large wall adapteras their primary supply. The new LTC4268-1 breaks thispower barrier by allowing for power of up to 35W for suchpower-hungry 2-pair PoE applications. The LTC4268-1provides a complete solution by integrating a high powerPD interface control with an Isolated fl yback controller.
The latest generation of Texas Instruments (TI) boardmountedpower modules utilizes a pin interconnect technologythat improves surface-mount manufacturability.These modules are produced as a double-sided surfacemount(DSSMT) subassembly, yielding a case-less constructionwith subcomponents located on both sides of theprinted circuit board (PCB). Products produced in theDSSMT outline use the latest high-efficiency topologiesand magnetic-component packaging. This providescustomers with a high-efficiency, ready-to-use switchingpower module in a compact, space-saving package. BothnonIsolated point-of-load (POL) switching regulators andthe Isolated dc/dc converter modules are being producedin the DSSMT outline.TI’s plug-in power product line offers power modules inboth through-hole and surface-mount packages. The surfacemountmodules produced in the DSSMT outline use asolid copper interconnect with an integral solder ball fortheir
The PCA9541 is a 2-to-1 I2C-bus master selector designed for high reliability dual masterI2C-bus applications where system operation is required, even when one master fails orthe controller card is removed for maintenance. The two masters (for example, primaryand back-up) are located on separate I2C-buses that connect to the same downstreamI2C-bus slave devices. I2C-bus commands are sent by either I2C-bus master and are usedto select one master at a time. Either master at any time can gain control of the slavedevices if the other master is disabled or removed from the system. The failed master isIsolated from the system and will not affect communication between the on-line masterand the slave devices on the downstream I2C-bus.
The ISO7220 and ISO7221 are dual-channel digital isolators. To facilitate PCB layout, the channels are orientedin the same direction in the ISO7220 and in opposite directions in the ISO7221. These devices have a logic inputand output buffer separated by TI’s silicon-dioxide (SiO2) isolation barrier, providing galvanic isolation of up to4000 V. Used in conjunction with Isolated power supplies, these devices block high voltage, isolate grounds, andprevent noise currents on a data bus or other circuits from entering the local ground and interfering with ordamaging sensitive circuitry.
The 87C576 includes two separate methods of programming theEPROM array, the traditional modified Quick-Pulse method, and anew On-Board Programming technique (OBP).Quick Pulse programming is a method using a number of devicepins in parallel (see Figure 1) and is the traditional way in which87C51 family members have been programmed. The Quick-Pulsemethod supports the following programming functions:– program USER EPROM– verify USER EPROM– program KEY EPROM– program security bits– verify security bits– read signature bytesThe Quick-Pulse method is quite easily suited to standardprogramming equipment as evidenced by the numerous vendors of87C51 compatible programmers on the market today. Onedisadvantage is that this method is not well suited to programming inthe embedded application because of the large number of signallines that must be Isolated from the application. In addition, parallelsignals from a programmer would need to be cabled to theapplication’s circuit board, or the application circuit board wouldneed to have logic built-in to perform the programming functions.These requirements have generally made in-circuit programmingusing the modified Quick Pulse method impractical in almost all87C51 family applications.
通過比較各種隔離數(shù)字通信的特點(diǎn)和應(yīng)用范圍，指出塑料光纖在隔離數(shù)字通信中的優(yōu)勢(shì)。使用已經(jīng)標(biāo)準(zhǔn)化的TOSLINK接口，有利于節(jié)省硬件開發(fā)成本和簡化設(shè)計(jì)難度。給出了塑料光纖的硬件驅(qū)動(dòng)電路，說明設(shè)計(jì)過程中的注意事項(xiàng)，對(duì)光收發(fā)模塊的電壓特性和頻率特性進(jìn)行全面試驗(yàn)，并給出SPI口使用塑料光纖隔離通信的典型應(yīng)用電路圖。試驗(yàn)結(jié)果表明，該設(shè)計(jì)可為電力現(xiàn)場(chǎng)、電力電子及儀器儀表的設(shè)計(jì)提供參考。
Abstract:
y comparing characteristics and applications area of various Isolated digital communications， this article indicates advantages of plastic optical fiber in Isolated digital communications. Using the standardized TOSLINK interface， it helps to control costs and difficulty in hardware development and design. Then it gives the hardware driver circuit of plastic optical fiber module， explains the noticed details in design process， gives results on the basis of the optical transceiver module voltage characteristics and frequency characteristics tests. Finally，it gives typical application circuit of the SPI communication port by using plastic optical fiber isolation .The results show that this design can be referenced for the power field， power electronics and instrumentation design.
The FPGA can realize a more optimized Digital controller in DC/DC Converters when compare to DSPs. In this paper, based on the FPGA platform, The theoretical analysis, characteristics, simulation and design consideration are given. The methods to implement the digital DC/DC Converters have been researched. The function module, state machine of digital DC/DC controller and high resolution DPWM with Sigma-
Delta dither has been introduced. They are verified by experiments on a 20 W, 300 KHz non-Isolated synchronous buck converters.
DDSCAT 7.3 is a freely available open-source Fortran-90 software package applying the “discrete
dipole approximation” (DDA) to calculate scattering and absorption of electromagnetic waves by targets
with arbitrary geometries and complex refractive index. The targets may be Isolated entities (e.g., dust
particles), but may also be 1-d or 2-d periodic arrays of “target unit cells”, which can be used to study
absorption, scattering, and electric ?elds around arrays of nanostructures.
This book is about multipoint cooperative communication, a key technology to
overcome the long-standing problem of limited transmission rate caused by inter-
point interference. However, the multipoint cooperative communication is not an
Isolated technology. Instead, it covers a vast range of research areas such as the
multiple-input multiple-outputsystem, the relay network, channel state information
issues, inter-point radio resource management operations, coordinated or joint
transmissions, etc. We suppose that any attempt trying to thoroughly analyze the
multipoint cooperative communication technology might end up working on a
cyclopedia for modern communication systems and easily get lost in discussing all
kinds of cooperative communication schemes as well as the associated models and
their variations.
ABSTRACTThe flyback power stage is a popular choice for single and multiple output dc-to-dc converters at powerlevels of 150 Watts or less. Without the output inductor required in buck derived topologies, such as theforward or push-pull converter, the component count and cost are reduced. This application note will reviewthe design procedure for the power stage and control electronics of a flyback converter. In these Isolatedconverters, the error signal from the secondary still needs to cross the isolation boundary to achieveregulation. By using the UC3965 Precision Reference with Low Offset Error Amplifier on the secondaryside to drive an optocoupler and the UCC3809 Economy Primary Side Controller on the primary side, asimple and low cost 50 Watt Isolated power supply is realized.
