外文文献及翻译

外文文献

（一）原文

DUAL FULL BRIDGE PROTECTED MOTOR DRIVER（A3976）The A3976 is designed to drive both windings of a bipolar stepper motor or bidirectionally control two DC Motors. Both H-Bridges are capable of continuous output currents of up to

+/- 500 mA and operating voltages to 30V. Free wheeling, substrate isolated diodes are included for output transient suppression when switching motors or other inductive loads. For each bridge the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. The ENABLE input, when held high, enables the respective output H-bridge. When both ENABLE pins are held low the device will enter SLEEP mode and consume less than 100mA. The 3976 is protected to ensure safe operation in harsh operating environments and was designed specifically for automotive applications. Protection circuitry will check for open or shorted load, motor lead short to ground or supply, VBB overvoltage, VCC undervoltage, and thermal shutdown. If any of these conditions are detected the outputs will be disabled and fault information will be output to diagnostic pins FAULT1 and FAULT2. The 3976 is supplied in a choice of two power packages, a 16-lead plastic DIP with a copper batwing tab (suffix ‘B’), and a 24-lead plastic SOIC with a copper batwing tab (suffix ‘LB’). In both cases, the power tab is at ground potential and needs no electrical isolation.

FEATURES

（1）30 V , ±500 mA Continuous Output Rating

（2）35V Load Dump Survival

（3）Output Short Circuit Protection

（4）Coded Fault Diagnostic Outputs

（5）Low Current Standby Mode

（6）Open Load Monitor

（7）Low Current Standby Mode

（8）VBB Over Voltage Shutdown

（9）Internal Thermal Shutdown Circuitry

（10）Internal Low Parasitic Free Wheeling Diodes

（11）Crossover Current Protection

ABSOLUTE MAXIMUM RATINGS

at TA = +25°C

Operating Supply Voltage, VBB .................... 30 V

Non-Operating Supply Voltage..................... 35 V Output Current, IOUT ............................±500 mA* Logic Supply Voltage, VCC.......................... 7.0 V Fault Output Voltage ................................... 7.0 V

Logic Input Voltage Range, VIN.......................... -0.3 V to VCC + 0.3 V

Package Power Dissipation (TA = +25°C), PD

A3976KLB..................................2.2 W

A3976KB ....................................2.9 W

Operating Temperature Range,

TA ..............................-40°C to +125°C

Junction Temperature, TJ .........................+150°C Storage Temperature Range, TS...............................-55°C to +150°C

* Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or a

junction temperature of 150°C.

PART NUMBER PACKAGE RØJA RØJT

A3976KLB24 Lead SOIC56︒C/W6︒C/W

A3973KB16 Lead DIP43︒C/W6︒C/W

Input Logic

PHASE ENABLE OUTA OUTB

X 0 OFF OFF

0 1 LOW HIGH

1 1 HIGH LOW

Fault Logic

Fault Condition FAULT1FAULT2

Thermal Shutdown LOW LOW

Short to Battery or Open Load LOW HIGH

Short to Ground HIGH LOW

Normal Operation HIGH HIGH

APPLICATION NOTES

Open Lead Protection. During normal PWM operation diagnostic circuitry will look for a minimum source current level after a bridge is signalled on. Additionally, the diode flyback is monitored on the proper output. The logic will signal a fault and disable the outputs if it determines that the current is below the minimum level AND no flyback is occurring. If the inductive load is too large, the current would take too long to reach the minimal level and a

false open load would be reported. It is recommended that the inductive load be less than

38mH.

Short Circuit Protection. Internal sense resistors in series with VBB and ground will

trip the fault circuitry if greater than 1.1A is detected. To prevent false overcurrent events due to reverse recovery spikes of the clamp diodes, the current monitor is blanked for 5us after a high side is signalled to turn on. If an additional input command follows after the initial fault, the selected pair of drivers will pulse on for the 5us blanking duration. The short circuit fault will remember the input state where the fault occurred and will wait for that particular logic state after the short has been removed before normal operation is allowed to resume.

Thermal Protection. Circuitry turns OFF all drivers when the junction temperature

reaches 170°C typically. It is intended only to protect the device from failures due to excessive junction temperatures and has a hysteresis of approximately 15°C.

Layout. The printed wiring board should use a heavy ground plane. For optimum electrical

and thermal performance, the driver should be soldered directly onto the board. The load supply pin, VBB, should be decoupled with an electrolytic capacitor (> 47 μF is recommended) placed as close to the device as possible

Enengy or Solar Enegry

Energy means the power which does work and drives machines. All living things (including humans) rely on the sun as a source of energy. Coal, petroleum, and natural gas are energy sources available today because organisms in the past captured sunlight energy and stored it in the complex organic molecules that made up their bodies, which were then compressed and concentrated. With the development of society, a large of energy sources have been used,such as coal, petroleum, natural gas, geothermal energy, nuclear fission power, nuclear fusion power, solar energy, and Hydrogen gas. however, under the circumstances, the quantity of energy source is limited. unlimited usage of energy source results in energy crisis. At present, most of the energy consumed by humans is produced from fossil fuels. The greatest recoverable fossil is in the form of coal and lignite. Although world coal resources are enomous and potentially can fill energy needs for a century or two, their utilization is limited by environmental disruption from mining and emissions of carbon dioxide and sulfur dioxide. These would become intolerable long before coal resources were exhausted. Only a small percentage of coal and lignite has been utilized to date, whereas much of the recoverable petroleum and natural gas has already been consumed. Petroleum has several characteristics that make it superior to coal as a source of energy. Its extraction causes less environmental damage than does coal mining. It is a more concentrated source of energy than coal, and it burns with less pollution, and it can be moved easily through pipes. These characteristics make it an ideal fuel for automobiles.

Since first commercial oil well in 1859, somewhat more than 100 million barrels of oil have been produced in the United States, most of it in recent years. In 1990 world petroleum

consumption was at a rate of about 65 million barrels per day. Projected use of petroleum and natural gas indicates rapid depletion. Alaskan oil can help the petroleum supply only temporarily. Peak world petroleum resources production will be reached within a few years. Since the first "energy crisis" of 1973-1974, some concrete actions have even taken place. However, the several-fold increase in crude oil prices since 1973 has extacted a toll. In the U.S. and other industrialized nations, the economy has been plagued by inflation, recession, unemployment, and obsolescence of industrial equipment. The economies of some petroleum-deficient developing countries have been devastated by energy prices.

Energy crisis was accompanied by worldwide shortages of some foods and minerals, followed in some cases by surpluses, such as the surplus wheat resulting from increased planting and a copper surplus resulting from the efforts of copper-producing nations to acpuire foreign currency by copper export.

As known to all,the availability and cost of energy has become dominant factors in society today. Obviously, solving the "energy crisis" makes good sense. Many schemes has been proposed for conserving present energy resources and for developing new ones. It is always possible to use less energy in any process. Therefore, energy engineer is created and developed. The first goal of energy engineer is to determine the methods by which energy utilization is reduced but the output remains the same, or even increases.The second goal is to determine which methods of using less energy are cost effective.

Conventional engineering techniques are used to evaluated the mechanisms of energy use. Economic considerations are of equal importance and life cycle cost and saving techniques are used to determine cost-effective measures. The evaluation focuses on those uses which are significant in the overall picture and attempts to determine those technical measures that can reduce usage and save money.

Meanwhile, looking for ideal energy sources is also very important to solve energy crisis. The recipe for an ideal energy source calls for one that is unlimited in supply, widely available, and inexpensive; it should not add to the earth's total heat burden or produce chemical air and water pollutants. Solar energy fulfills all of these criteria. Solar energy does not add excess heat to that which must be radiated from the earth. On a global basis, utilization of only a small fraction of solar energy reaching the earth could provide for all energy needs.

Solar energy is unlimited in supply, but its exploitation and utilization are limited owing to the limitation of technology and conditions. Solar energy utilization needs an enormous amount of land, and there are economic and environmental problems related to the use of even a fraction of this amount of land for solar energy collection. Certainly, many residents of Arizona would not be pleased at having so much of the state devoted to solar collectors, and some environmental groups would protest the resultant shading of rattlesnake habitat. Solar power cells for the direct conversion of sunlight to electricity have been developed and are widely used for energy in space vehicles. With present technology, however, they remain too expensive for large-scale generation of electricity. Therefore, most schemes for the utilization of solar power depend upon the collection of thermal energy, followed by conversion to electrical energy. The simplest such approach involves focusing sunlight on a steam-generating bioler. Parabolic refkectors can be used to focus sunlight on pipes

containing heat-transporting fluids. Selective coatings on these pipes can be used so that only a small percentage of incident energy is reradiated from the pipes.

（二）翻译

全双桥电机保护驱动器（A3976）

A3759是一种用来驱动双极性步进电机双绕组的单片集成电路，也可以用来双向控制两台电动机。双H桥能够连续输出±～500mA的电流和30V的运行电压。当开关电动机或者是其他感性负载时，衬底隔离的续流二极管可以起到输出抑制的作用。对于每一个H桥，相位（PHASE）输入端能通过选择合适的电源和驱动器控制电流的极性，使能（ENABLE）输入置成高电平时，可以使各自的H桥导通。当2个ENABLE引脚都被置成低电平时，芯片进入睡眠状态，消耗不到100微安的电流。

A3976附加了许多保护功能，以确保电路在苛刻得环境下工作，并且为了应用于汽车而进行了特别设计。保护电路能够检测到负载开路或者短路、电动机短路接地或短路接电源、功率电源VBB过电压、逻辑电源VCC欠电压、过热关断等。如果检测到这些，输入就会被禁止，故障信息通过诊断引脚即为FAULT1和FAULT2输出。

芯片特点：

（1）具有30V，±500mA的连续输出能力

（2）具有35V清除残存功能

（3）具有输出短路保护

（4）可输出编码的故障诊断信号

（5）内部含有开路负载监视器

（6）设有弱电流待命模式

（7）设有负载开路监视器

（8）具有功率电路电源VBB过电压关断功能

（9）内部含有热关断电路

（10）内部含有低寄生续流二极管

（11）具备交叉式电流保护功能

A3976工作环境与性能参数为：

（1）运行供电电压VBB：30V

（2）输出电流IOUT：±500mA

（3）逻辑供电电压VCC：7.0V

（4）故障输出电压：7.0V

（5）逻辑输入电压范围VIN：-0.3V～VCC+0.3V

（6）芯片功耗（TA+25°C）PD：2.2W（A3976KLB），2.9W（A3976KB）（7）工作温度范围TA：-44～125°C

（8）存储温度范围TS：-55～15.°C

型号封装RØJA RØJT

A3975KLB 24脚（SOIC）56 C/W 6 C/W

A3975KB 16脚（DIP）43 C/W 6 C/W

输入逻辑关系

PHASE ENABLE OUTA OUTB

X 0 OFF OFF

0 1 LOW HIGH

1 1 HIGH LOW

故障输出信号与故障种类的关系

故障情况FAULT1 FAULT2

过热关断LOW LOW

与电池短路或负载开路LOW HIGH

与地短路HIGH LOW

正常运行HIGH HIGH

使用须知：

开环保护电路：在正常情况下，当一个桥路被保护后，PMW操作诊断电路将会监视最低

电源电流。同时，扫描作用的二极管将会监视输出信号是否正确。如果输出低于最小值

或监视电路出现故障，逻辑电路将会输出错误信号并且停止输出。如果感性负载过大，电流将会持续很长时间以接近最小值，并且将会报告一个错误的开环信息。因此感性负载应小于38mH。

短路保护电路：当检测到大于1.1A的电流后，VBB与地的地的检测电阻将会访问故障电路。为防止由于钳位二极管的峰值反转而产生过电流事件的发生，当前监视器在高位端被通知开启后自动暂停5微秒。当出现一个故障引起的中断后，其对应的驱动部分将会停止5微秒。在正常操作被允许执行之前，短路故障将会存储故障发生的输入状态并且会等待故障被移除的特殊逻辑信号的到达。

热保护电路：当温度达到170°C时，保护电路将会关闭所有的驱动器。这是为了防止由于温度过高而产生故障，温度范围为15°C左右。

电路板中部件的布局：为了达到最佳电特性与温度特性，驱动部件应该紧贴着印刷板进行焊接。负载电源引脚VBB应接一个电解电容（建议大于47μF）作为缓冲装置，并且应该尽量接近驱动部件进行焊接。

能源与太阳能

能源就是能够用于工作和驱动机器的能量。所有的生物（包括人类）都是依靠阳光作为能量的来源。煤、石油和天然气都是可以利用的能源，这些能源都是过去的生物体在太阳光能源的作用下生成复杂的存储这些能源有机分子结构经过长时间的压缩集中后生成的。大量的能源已经被使用，如煤炭、石油、天然气、地热资源、核聚变能源、核裂变能源、太阳能和氢气等。然而，在这种情况下，由于许多能够产生能量的资源是不可再生的，大量的使用这些能源可能会引起能源危机。

目前，人类的能源消耗主要体现在燃料资源的消耗上。现在的固体状能源主要是煤炭，目前已知的加上潜藏的煤炭储量最多可使用一到两个世纪，而且煤炭的开采和使用会破坏环境并且产生大量的二氧化碳与二氧化硫。当煤炭资源用尽前这些影响将会越来越恶劣。煤炭在能源的利用方面的比例已经越来越低，而石油和天然气正在被大量的使用着。作为能源，石油比煤炭有更大的优势。其开采地比煤炭更为集中因此对环境的破坏要少，其燃烧产生的污染物要比煤炭少，而且石油可以很容易的通过管道进行运输。同时这些优势使石油成为理想的汽车燃料。

自从1859年第一个商业油田的建成以来，美国已经生产了超过100万桶石油，其中

大部分是在最近几年生产的。1990年全世界约消耗了65万桶石油。石油与天然气资源在迅速的消耗着，阿拉斯加出产的石油只能暂时缓解石油的供应危机。世界石油的生产将在几年之内达到最高值。

自从1973～1974年的第一次“能源危机”以来，已经出现了一些具体的措施。然而，自1973年以来，原油的价格已经提高了若干倍。美国和其他工业化国家一直受到通货膨胀、经济衰退、大批的失业和工业设备的过时的困扰。一些石油不足的发展中国家由于能源价格的关系其经济已经遭到破坏。

在能源危机的同时，世界范围内还有一些食品和矿产资源的短缺，其次一些物品的生产则出现过剩，如小麦和铜的生产过剩，一些铜生产国将铜以铜币的形式出口。

众所周知，能源的供应和成本已经成为当今社会的一个主要的话题。很显然，解决“能源危机”是非常有意义的。目前已经有许多节约能源和发展新能源的计划被提出来。在任何领域节约能源都是可行的。因而，能源工程师这个职业产生并迅速发展起来。能源工程师的第一个提议是想办法减少能源的消耗同时保证产量不变甚至有所提高，第二个提议是寻找降低能源成本的方法。

传统的工程技术被用来评估能源利用的技术。周期成本与用于节省资金的方法与经济利益同等重要。评价的重点是整个大局中的重要性和减少浪费和使用的资金的方法。

同时，寻找更为理想的能源是非常重要的。解决能源危机的一种理想的能源的要求应该是无限的供应、能够被广泛的使用、价格低廉、而且其使用后不会添加地球的总热量的负担或者不会产生化学空气和水污染物的排放。太阳能满足这些标准，其产生的多余的热量会从地球辐射出去。而且利用照射到地球的一小部分太阳能就能够提供地球所需的能源。

太阳能的供应是无限的，但是由于技术和条件的限制，其开发和利用是有限的。太阳能的利用需要大量的土地，还有经济和环境方面的要求，而且这一部分土地上太阳能的收集也只能达到一小部分。当然，亚利桑那州的许多居民渴不喜欢国家大力发展太阳能的收集，而且一些环保组织也因为太阳能的收集对响尾蛇的生活习性等产生的影响而抗议太阳能收集装置的实行。

太阳能电池能够将太阳能直接转化为电能，而且已经广泛应用于空间飞行器能源的提供。然而，以目前的技术水平如果应用于大规模发电其代价于昂贵。因此，目前大多数太阳能发电方式仍旧是首先将太阳能转化为热能，然后再将热能转化为电能。这种方

式目前最简单的设计是蒸汽发电装置，收集到的太阳能通过管道中的载热气体进行输送。这种管道使用涂层能够使运输过程中的入射能量只有很少部分的流失。