4679.基于嵌入式处理器的VLSI芯片的温度自动控制 外文翻译

1、毕业设计/论文外 文 文 献 翻 译系 别 自动化 专 业 班 级 自动化 0601 姓 名 评 分 指 导 教 师 华中科技大学武昌分校 20 年 月 日 毕业设计/论文外文文献翻译要求：1外文文献翻译的内容应与毕业设计/论文课题相关。2外文文献翻译的字数：非英语专业学生应完成与毕业设计/论文课题内容相关的不少于2000汉字的外文文献翻译任务（其中，汉语言文学专业、艺术类专业不作要求），英语专业学生应完成不少于2000汉字的二外文献翻译任务。格式按华中科技大学武昌分校本科毕业设计/论文撰写规范的要求撰写。3外文文献翻译附于开题报告之后：第一部分为译文，第二部分为外文文献原文，译文与原文均需单

2、独编制页码（底端居中）并注明出处。本附件为封面，封面上不得出现页码。4外文文献翻译原文由指导教师指定，同一指导教师指导的学生不得选用相同的外文原文。基于嵌入式处理器的vlsi芯片的温度自动控制摘要本文介绍了基于嵌入式处理器的vlsi芯片的温度自动控制，同时利用温度传感器lm35和arm处理器lpc2378来完成设计。由于vlsi芯片密度非常高，同时芯片在工作时很快得到加热，如果不能研制出能是它快速冷却的方法，芯片的性能将会受到很大影响。在目前的工作中，将传感器放置在非常接近接近到ic集成电路的位置来采集芯片的温度，通过由arm处理器产生的pwm信号来控制集成电路旁风扇的转速。在硬件电路中也提供

3、了一个蜂鸣器，在无法控制风扇或者ic集成电路的过热的情况下都会发出警报。整个过程的实现需要制定一个合适的嵌入式c程序。关键词：温度传感器，arm处理器，超大规模集成电路芯片，无刷直流电动机1.介绍 随着vlsi超大规模集成电路技术的惊人发展，雄心勃勃的ic设计师正试图将更多的晶体管用更小的体积实现更多的功能。因此，该集成电路运行速度更快，产生更多的热量而造成的新的问题。举例来说，现在世界上的的cpu芯片 变得越来越小，几乎没有空间散热。若消耗100 w的功率的话，峰值功率密度为400-500 w/cm2，并可能持续上升。随着芯片温度的升高会影响性能的参数变化，从而减少芯片的工作频率和影响时序的

4、规范。因此，在允许的条件范围内，为了让高速芯片能得到最好的工作效率和最长的运行时间，必须要让芯片在短时间内冷却下来。高速芯片所能允许的最高温度，取决于程序的参数规格，以及芯片的设计。 在各种不同的冷却技术中，人们通常使用散热片，热管，风扇以及时钟节流。在这些技术中，风扇可以快速高效的降低高速芯片的温度，但它们也产生大量的噪音。这种噪声可以通过不同的方法来降低，根据风扇转速是由温度来控制，当温度低时，风扇的转速降低；随着温度的提高，风扇的速度会随着提升。另一个有效地的方法是时钟节流，即减少了时钟速度，降低功耗。但它也降低了系统性能和系统运行速度。本工作的目标是，设计一个硬件系统能控制直流无刷电机

5、风扇的转速，芯片的温度则由传感器lm35进行采集.。lm35系列是精密的集成电路温度传感器，其输出电压与采集到的摄氏的温度成线性比。因此，lm35系列比一般的传感器拥有优势，因为我们可以直接通过电压值来确定摄氏温度值。lm35不需要校准或微调，便可以提供提供在室温±0.25 精度和-55 +150温度范围。由于lm35系列不需要校准，所以该传感器比较经济，低成本。lm35的低输出阻抗，线性输出和精确的校准的特点使固有接口的读数和控制电路特别容易。它同时可用于单电源输出和多电源输出。由于它只需要60微安的电流供应，所以它自身产生的热量较低，在真空中约升温0.1 。lm35 在-55 +

6、150温度范围内可以正常的工作，而lm35c可工作的温度范围为-40 +110。lm35系列可封装在密封的to - 46晶体管内，而lm35c，lm35ca和lm35d也可用塑胶to-92晶体管封装。lm35d也可以用8引脚小型封装和塑料的to - 220封装。由arm7tdmi处理器所产生的pwm信号来控制直流风扇电动机两端的电压。pwm信号的变化与lm35温度传感器的电压输出同步。因此，这整个项目的重要组成部分是温度传感器。 2 描述 在arm处理器为基础的温度自动控制系统，温度传感器输出是由芯adc来控制。而adc的输出是与ic相连，ic l293d的驱动信号直接送到直流风扇电机中，系统

7、框图如图1所示。lcd图形液晶显示器（128x64像素）的接口与arm lpc 2378处理器相连，来显示该集成电路的温度和风扇转速。蜂鸣器同样是连接arm处理器，在无法控制风扇和芯片过热的情况下会发出警报，整个电路图如图2所示。 图1 系统框图图2电路图3 软件介绍 目前的工作是使用arm iar工作台ide，嵌入式c程序和使用flash isp工具处理器进行嵌入式开发。arm iar的工作台ide是一个非常强大的集成开发环境（ide），允许开发和管理完整的嵌入式应用项目。在系统编程这一环境下我们可以采用引导加载器软件和使用一个串行端口进行编程或重新编程闪存记忆体中的程序。lpc2387单片

8、机是基于16/32位的arm7tdmi-s cpu的实时仿真，它同时结合了512 kb嵌入式闪存单片机的特点。128位宽度的存储器接口和独特的加速结构使32位代码执行在最大时钟频率下运行。在thumb模式下，中断服务程序和dsp算法的关键性能能提高30以上。对于重要代码应用，其他16位代码在thumb模式性能损失可减少超过30。lpc2387是多用途串行通信应用的理想选择。它由一10/100以太网媒体访问控制器（mac），4个端点的usb全速设备内存，4个uart，两个can通道，一个spi接口，两个同步串行端口（ssp）的，3 个i2c接口，和一个i2s接口组成。这种融合了串行通信接口与频率

9、为4 mhz内部振荡器，64 kb的sram记忆体，16个以太网，16 kb的usb ，连同2 kb的电池供电sram的功能非常适合于协议转换器的转换。32位定时器，10位dac，一个pwm单元，一个can控制装置，以及多达70个的gpio线路和12个外部中断引脚使这个单片机特别适合应用在工业控制和医疗系统等。lpc2378单片机提供芯片的引导加载器软件，允许在串行通道的内部快闪记忆体内编程 。飞利浦提供了一个在系统实用程序即所谓闪光魔术软件编程。 4 结果与结论 基于嵌入式arm处理器的温度控制系统的设计和实施已经完成了。为了验证设计的有效性，温度传感器被放在一个比室内温度高的烤箱内。这时风

10、扇在全速运行并发现温度重返正常温度。我们重复的用各种不同的超大规模集成电路来做这个实验，像奔腾处理器芯片，fpga芯片等。我们将温度传感器放在接近奔腾处理器的计算机的位置，慢慢的我们观察到风扇的速度自动增加，芯片的温度被控制。这些结果在lcd液晶显示面板上可以看见。虽然目前的系统在特定环境下是行之有效的，但以下结论仍然是值得强调。 一般情况下，使用控制风扇速度或时钟节流的方式来控制温度的条件是必须及时的检测出目标芯片的温度。这个实验中通过放置一个温度传感器在目标芯片旁边，在某些情况下，也可以放在被测物体下方或者是散热器下。以这种方式检测高速芯片的温度与实际温度较为接近，但也有可能测量温度比管芯

11、温度上升时温度要低。因此，电路板或散热片温度和高速芯片管芯的温度必须相关。当然如果有很多高速芯片是更好的选择。许多cpu，fpga和其他高速集成电路包含一个热二极管，其实是一个连接双极晶体管的二极管。使用远程二极管温度传感器连接到这个热二极管，得出的结果可以与直接测量vlsi芯片一样精确。这不仅消除了目标ic的封装与室外温度有较大的温差所产生的误差，它也消除了芯片从几秒钟到几分钟内由于温度变化作出反应的延误。 还有一个缺点，有关风扇转速控制。一般情况下，风扇转速通过调整风扇的电源电压来控制。这是通过调整一个低频约50 hz 的pwm信号的占空比变化来调整风扇的速度。这种方法价格低廉，也很有效率

12、。但是，这种方法的缺点是由于脉冲电压的性质，它使风扇的噪音有点大。pwm波形的快速触发沿导致风扇机械结构产生移动，这是产生噪音的一个原因。 在一些系统中，限制风扇的速度变化率也是重要的。如果该系统与用户接近的话这一点是很关键的。在某些环境中，只需切换风扇的开关或改变速度可以让温度变化。但是，当用户在系统附近时，在风扇的速度的突然变化会产生非常恼人的噪音。因此，为了避免这些影响，风扇的驱动器信号必须限制在一个可接受范围内。 5.未来的工作前景 在目前的工作温度是由温度传感器lm35来采集，电机的转速是通过改变控制的处理器产生的pwm脉宽来控制。但lm35温度传感器并不能做到非常精确地采集温度，即

13、使我们让lm35温度传感器非常接近集成电路处理器或 vlsi芯片。因此，我们可以使用一个远程二极管温度传感器连接到热二极管，这种措施的直接测出高速集成电路的温度，检测出的结果非常精确。另一个重要方面是各种传感器的远程温度高达五个传感渠道，可以将检测到的高速芯片的温度数据传送到微控制器。风扇转速的监测与多渠道风扇转速调节器可以有效的控制温度。外部微控制器的命令可提供可靠的控制电源电压来监测风扇转速与调节多渠道风扇转速。对于这个简单的由maxim max6660和max6653组成的集成电路。第一个ic可以检测到远程温度然后通过温度来控制风扇风速。它由内部晶体管产生一个直流电源电压给风扇供电。第二

14、个ic也执行类似的功能，但驱动器由外部晶体管产生pwm波形。两个集成电路都包含完整的热故障监测系统，如果高速芯片太热，系统会自动关闭。因此，目前的工作可以使用上述技术进一步提高。原文出处：by:narasimha murthy yayavaram;saritha chappidi;sukany velamakuri.sensors & transducers journal,2009,vol.100, no.1embedded processor based automatic temperature control of vlsi chipsabstractthis paper pr

15、esents embedded processor based automatic temperature control of vlsi chips, using temperature sensor lm35 and arm processor lpc2378. due to the very high packing density, vlsi chips get heated very soon and if not cooled properly, the performance is very much affected. in the present work, the sens

16、or which is kept very near proximity to the ic will sense the temperature and the speed of the fan arranged near to the ic is controlled based on the pwm signal generated by the arm processor. a buzzer is also provided with the hardware, to indicate either the failure of the fan or overheating of th

17、e ic. the entire process is achieved by developing a suitable embedded c program. keywords: temperature sensor, arm processor, vlsi chips, brushless dc motor1.introductionwith the phenomenal developments in vlsi technology, the ambitious ic designers are trying to put more transistors in to smaller

18、packages. so, the ics run at higher speeds and produce large amount of heat which creates the problem of thermal management. for example, nowadays the cpu chips are becoming smaller and smaller with almost no room for the heat to escape. the total power dissipation levels now reside on the order of

19、100 w with a peak power density of 400-500 w/cm2, and are still steadily climbing. as the chip temperature increases its performance is very much degraded by parameters shift, decrease in operating frequencies and out-of specification of timings. so the high speed chips must be cooled to maintain go

20、od performance for the longest possible operating time and over the widest possible range of environmental conditions. the maximum allowable temperature for a high speed chip to meet its parametric specifications depends on the process and how the chip is designed.among the various cooling technique

21、s, heat sinks, heat pipes, fans and clock throttling are usually employed. among these techniques, fans can dramatically reduce the temperature of a high speed chip,but they also generate a great deal of acoustic noise. this noise can be reduced significantly by varying ,the fans speed based on temp

22、erature i.e. the fan can turn slowly when the temperature is low and canspeed up as the temperature increases.the other prominent method is clock throttling i.e. reducing the clock speed to reduce power dissipation. but it also reduces the system performance and the systems functionality is lost.so,

23、 the objective of the present work is, to design a hardware system consisting of a brushless dc motor fan whose speed is controlled based on the temperature of the chip, sensed by the sensor lm35.the lm35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly p

24、roportional to the celsius (centigrade) temperature. the lm35 thus has an advantage over linear temperature sensors calibrated in kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient centigrade scaling. the lm35 does not require anyexternal ca

25、libration or trimming to provide typical accuracies of ±14°c at room temperature and ±34°c over a full 55 to +150°c temperature range. low cost is assured by trimming and calibration at the wafer level. the lm35s low output impedance, linear output, and precise inherent cali

26、bration make interfacing to readout or control circuitry especially easy. it can be used with single power supplies, or with plus and minus supplies. as it draws only 60 a from its supply, it has very low selfheating, less than 0.1°c in still air. the lm35 is rated to operate over a 55° to

27、 +150°c temperature range, while the lm35c is rated for a 40° to +110°c range (10° with improved accuracy). the lm35 series is available packaged in hermetic to-46 transistor packages, while the lm35c, lm35ca, and lm35d are also available in the plastic to-92 transistor package.

28、the lm35d is also available in an 8-lead surface mount small outline package and a plastic to-220 package. to monitor the voltage at the terminals of the dc motor fan, the pwm signal is generated by the arm7tdmi processor. this pwm signal is changed in accordance to the output of the lm35temperature

29、 sensor. so the important component of this entire project is the temperature sensor.2. descriptionin arm processor based automatic temperature control system, the output of the temperature sensor is fed to the on chip adc and the output of the adc is given to the l293d driver ic which in turn is fe

30、d to dc motor fan as shown in the block diagram in fig. 1. a graphic lcd (128x64 pixels) is interfacedto the arm lpc 2378 processor to display the temperature of the ic and the speed of the fan. a buzzer is also connected to the processor which gives an indication, in case of the failure of the fan

31、or overheating of the chip beyond some level. the entire circuit diagram is shown in fig. 2.fig. 1. block diagram.fig. 2. circuit diagram.3. software descriptionthe present work is implemented using arm iar workbench ide and the necessary embedded c program is developed and dumped into the embedded

32、processor using flash magic isp utility. the arm iar workbench ide is a very powerful integrated development environment (ide) that allows you to develop and manage complete embedded application projects. in-system programming is programming or reprogramming the on-chip flash memory, using the boot-

33、loader software and a serial port. the lpc2387 microcontroller is based on a 16-bit/32-bit arm7tdmi-s cpu with real-time emulation that combines the microcontroller with 512 kb of embedded high-speed flash memory.a 128-bit wide memory interface and unique accelerator architecture enable 32-bit code

34、execution at the maximum clock rate. for critical performance in interrupt service routines and dsp algorithms, this increases performance up to 30 % over thumb mode. for critical code size applications, the alternative 16-bit thumb mode reduces code by more than 30 % with minimal performance penalt

35、y.the lpc2387 is ideal for multi-purpose serial communication applications. it incorporates a 10/100 ethernet media access controller (mac), usb full speed device with 4 kb of endpoint ram,four uarts, two can channels, an spi interface, two synchronous serial ports (ssp), threei2c interfaces, and an

36、 i2s interface. this blend of serial communications interfaces combined with an on-chip 4 mhz internal oscillator, 64 kb sram, 16 kb sram for ethernet, 16 kb sram for usb and general purpose use, together with 2 kb battery powered sram makes this device very well suited for communication gateways an

37、d protocol converters. various 32-bit timers, an improved 10-bit adc, 10-bit dac, one pwm unit, a can control unit, and up to 70 fast gpio lines with up to 12 edge or level sensitive external interrupt pins make this microcontroller particularly suitable for industrial control and medical systems.th

38、e lpc2378 microcontroller provides on-chip boot-loader software that allows programming of the internal flash memory over the serial channel. philips provides a utility program for in-system programming called flash magic software.4. results and conclusionsembedded arm processor based automatic spee

39、d control dc motor fan is designed and implemented.to test the validity of the design, the temperature sensor is kept inside a small oven and its temperature is increased beyond the room temperature. now the fan is operated to run with full speed and the temperature is found to comeback to normal te

40、mperature. this is repeated with various vlsi chips like pentium processor, fpga chips etc. now the temperature sensor is kept very near to the pentium processor of the computer and it is observed that, as the time lapses the speed of the fan is automatically increased and the temperature of the chi

41、p is found to be controlled. these results are displayed on lcd panel. though the present system is working well in the given environment, still it is worthwhile to highlight the following conclusions. normally, controlling fan speed or clock throttling based on temperature requires that the tempera

42、ture of the high speed chip should be first measured. this is done by placing a temperature sensor close to the target chip either directly next to it or in some cases, under it or on the heat sink. the temperature measured in this way corresponds to that of the high speed chip, but can be significa

43、ntly lower and the difference between measured temperature and the actual die temperature increases as the power dissipation increases. so, the temperature of the circuit board or heat sink must be correlated to the die temperature of the high speed chip. of course a better alternative is possible w

44、ith a number of high speed chips. many cpus, fpgas and other high speed ics include a thermal diode which is actually a diode connected bipolar transistor, on the die. using a remote diode temperature sensor connected to this thermal diode, the temperature of the high speed ics die can be measured d

45、irectly with an excellent accuracy. this not only eliminates the large temperature gradients involved in measuring temperature outside the target ics package, but it also eliminates the long thermal time constants,from several seconds to minutes, that cause delays in responding to die temperature ch

46、anges.there is also a drawback in fan speed control. normally the fan speed is controlled by adjusting the power supply voltage of the fan. this is done by a low-frequency pwm signal, usually in the range of about 50 hz, whose duty cycle is varied to adjust the fans speed. this is inexpensive and al

47、so efficient. but the disadvantage of this method is that it makes the fan somewhat nosier because of the pulsed nature of the power supply. the pwm waveforms fast edges cause the fans mechanical structure to move, which is easily audible.in some systems, it is also important to limit the rate of change of the fan speed. this is critical when the system is in close proximity to users. simply switching a fan on and off or changing speed immediately as temperature changes is acceptable in some environments. but when users are in nearby, the sudden changes in fans noise are highly annoying. so