The LTC®3610 is a high power monolithic synchronousstep-down DC/DC regulator that can deliver up to 12Aof continuous output current from a 4V to 24V (28Vmaximum) input supply. It is a member of a high currentmonolithic regulator family (see Table 1) that featuresintegrated low RDS(ON) N-channel top and bottomMOSFETs. This results in a high effi ciency and highpower density solution with few external components.This regulator family uses a constant on-time valleycurrent mode architecture that is capable of operatingat very low duty cycles at high frequency and with veryfast transient response. All are available in low profi le(0.9mm max) QFN packages.
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.
針對(duì)目前汽車追尾事件頻發(fā)問(wèn)題，提出一種防汽車車前和車后追尾的安全裝置設(shè)計(jì)。該設(shè)計(jì)以高性能、低功耗的8位AVR微處理器ATmega8L為核心，結(jié)合霍爾式車速傳感器、激光雷達(dá)測(cè)距裝置和MMA7260QT加速度傳感器，能夠兼顧車前和車后，摒棄以往設(shè)計(jì)中只考慮車前或車后單一性缺點(diǎn)，尤其適用于高速、夜晚或新手行車。
Abstract:
Aiming at the high frequency of vehicle rear-end collision，a safe device design of anti-vehicle rear-end collision is presented.In the design，the high-performance，low-power8-bit AVR microprocessor ATmega8L is utilized as a core combined with Hall-type speed sensor，laser-radar ranging devices and the acceleration sensor MMA7260QT.The design considers both the front and back of a car，and overcomes the drawbacks of former designs in which only the front or the back of the car is considered，so it is especially suitable for high-speed，night or the beginner’s driving.
介紹了當(dāng)前普通標(biāo)記機(jī)控制系統(tǒng)現(xiàn)狀及其存在缺點(diǎn)，給出氣動(dòng)標(biāo)記機(jī)及相頻修正PWM模式的工作原理。采用ATmega16單片機(jī)和USB轉(zhuǎn)換RS232接口器件CH341T實(shí)現(xiàn)驅(qū)動(dòng)控制系統(tǒng)與PC的實(shí)時(shí)通訊，標(biāo)記控制系統(tǒng)可升級(jí)到USB接口。采用基于ATmega16的相頻修正PWM替換555振蕩電路產(chǎn)生的PWM，可直接通過(guò)軟件調(diào)整PWM信號(hào)。使用達(dá)林頓三極管TIP122替代直流繼電器驅(qū)動(dòng)高頻電磁閥，使得電磁閥驅(qū)動(dòng)電路簡(jiǎn)單，成本低廉。該控制系統(tǒng)已成功應(yīng)用于氣動(dòng)標(biāo)記機(jī)。
Abstract:
In this paper,the actuality and demerit of the common gas marking machine control systems are described.The operation principle of the gas marking machine and the phase and frequency correct PWM of ATmega16is introduced.The real-time communication between the driving control system and PC by CH341T which its function is translated USB to RS232is realized,the control systems is updated grade to USB interface.The PWM signal can be adjustable by software for the555surge circuit was substituted by the phase and frequency.The high frequency electromagnetic value’s driving circuit by DC relay is replaced by TIP122,therefore,the circuit is become simple and the cost cheap.The control systems has been widely used in gas marking machine.
Agilent AN 154 S-Parameter Design Application Note S參數(shù)的設(shè)計(jì)與應(yīng)用
The need for new High-Frequency, solid-state circuitdesign techniques has been recognized both by microwaveengineers and circuit designers. These engineersare being asked to design solid state circuitsthat will operate at higher and higher frequencies.The development of microwave transistors andAgilent Technologies’ network analysis instrumentationsystems that permit complete network characterizationin the microwave frequency rangehave greatly assisted these engineers in their work.The Agilent Microwave Division’s lab staff hasdeveloped a high frequency circuit design seminarto assist their counterparts in R&D labs throughoutthe world. This seminar has been presentedin a number of locations in the United States andEurope.From the experience gained in presenting this originalseminar, we have developed a four-part videotape, S-Parameter Design Seminar. While the technologyof high frequency circuit design is everchanging, the concepts upon which this technologyhas been built are relatively invariant.The content of the S-Parameter Design Seminar isas follows:
This paper presents the key circuits of a 1MHz bandwidth, 750kb/s GMSK transmitter. The fractional-N synthesizer forming the basis of the transmitter uses a combined phasefrequency
detector (PFD) and digital-to-analog converter (DAC) circuit element to obtain >28dB high frequency noise reduction when compared to classicalfrequency synthesis.
The new digital radio system DAB (Digital Audio Broadcasting, nowadays often called
Digital Radio) is a very innovative and universal multimedia broadcast system which will
replace the existing AM and FM audio broadcast services in many parts of the world in
the future. It was developed in the 1990s by the Eureka 147/DAB project. DAB is very
well suited for mobile reception and provides very high robustness against multipath
reception. It allows use of single frequency networks (SFNs) for high frequency
efficiency.
The PW2312 is a high frequency, synchronous, rectified, step-down, switch-mode converter withinternal power MOSFETs. It offers a very compact solution to achieve a 1.5A peak output currentover a wide input supply range, with excellent load and line regulation.The PW2312 requires a minimal number of readily available, external components and is available ina space saving SOT23-6 package.
