霍尔传感器简介.doc

霍尔效应-百度百科百科名片霍尔效应是磁电效应的一种，这一现象是美国物理学家霍尔（A.H.Hall，18551938）于1879年在研究金属的导电机构时发现的。当电流垂直于外磁场通过导体时，在导体的垂直于磁场和电流方向的两个端面之间会出现电势差，这一现象便是霍尔效应。这个电势差也被叫做霍尔电势差。目录发现 解释 相关反应 本质 应用 发展编辑本段发现霍尔效应在1879年被E.H. 霍尔发现，它定义了磁场和感应电压之间的关系，这种效应和传统的感应效果完全不同。当电流通过一个位于磁场中的导体的时候，磁场会对导体中的电子产生一个垂直于弟子运动方向上的的作用力，从而在导体的两端产生电压差。 虽然这个效应多年前就已经被大家知道并理解，但基于霍尔效应的传感器在材料工艺获得重大进展前并不实用，直到出现了高强度的恒定磁体和工作于小电压输出的信号调节电路。根据设计和配置的不同，霍尔效应传感器可以作为开/关传感器或者线性传感器。 霍尔效应编辑本段解释在导体上外加与电流方向垂直的磁场，会使得导线中的电子与电洞受到不同方向的洛伦兹力而往不同方向上聚集，在聚集起来的电子与电洞之间会产生电场，此一电场将会使后来的电子电洞受到电力作用而平衡掉磁场造成的洛伦兹力，使得后来的电子电洞能顺利通过 霍尔效应不会偏移，此称为霍尔效应。而产生的内建电压称为霍尔电压。 方便起见，假设导体为一个长方体，长度分别为a,b,d，磁场垂直ab平面。电流经过ad，电流I = nqv(ad)，n为电荷密度。设霍尔电压为VH，导体沿霍尔电压方向的电场为VH / a。设磁场强度为B。 霍尔效应推导? 编辑本段相关反应量子霍尔效应 热霍尔效应：垂直磁场的导体会有温度差。 Corbino效应：垂直磁场的薄圆碟会产生一个圆周方向的电流。 自旋霍尔效应 编辑本段本质固体材料中的载流子在外加磁场中运动时，因为受到洛仑兹力的作用而使轨迹发生偏移，并在材料两侧产生电荷积累，形成垂直于电流方向的电场，最终使载流子受到的洛仑兹力与电场斥力相平衡，从而在两侧建立起一个稳定的电势差即霍尔电压。正交电场和电流强度与磁场强度的乘积之比就是霍尔系数。平行电场和电流强度之比就是电阻率。大量的研究揭示：参加材料导电过程的不仅有带负电的电子，还有带正电的空穴。 编辑本段应用霍尔效应在应用技术中特别重要。霍尔发现，如果对位于磁场(B)中的导体(d)施加一个电压(Iv)，该磁场的方向垂直于所施加电压的方向，那么则在既与磁场垂直又和所施加电流方向垂直的方向上会产生另一个电压(UH)，人们将这个电压叫做霍尔电压，产生这种现象被称为霍尔效应。好比一条路, 本来大家是均匀的分布在路面上, 往前移动. 当有磁场时, 大家可能会被推到靠路的右边行走. 故路 (导体) 的两侧, 就会产生电压差. 这个就叫“霍尔效应”。根据霍尔效应做成的霍尔器件，就是以磁场为工作媒体，将物体的运动参量转变为数字电压的形式输出，使之具备传感和开关的功能。 讫今为止，已在现代汽车上广泛应用的霍尔器件有：在分电器上作信号传感器、ABS系统中的速度传感器、汽车速度表和里程表、液体物理量检测器、各种用电负载的电流检测及工作状态诊断、发动机转速及曲轴角度传感器、各种开关，等等。 例如汽车点火系统，设计者将霍尔传感器放在分电器内取代机械断电器，用作点火脉冲发生器。这种霍尔式点火脉冲发生器随着转速变化的磁场在带电的半导体层内产生脉冲电压，控制电控单元（ECU）的初级电流。相对于机械断电器而言，霍尔式点火脉冲发生器无磨损免维护，能够适应恶劣的工作环境，还能精确地控制点火正时，能够较大幅度提高发动机的性能，具有明显的优势。 用作汽车开关电路上的功率霍尔电路，具有抑制电磁干扰的作用。许多人都知道，轿车的自动化程度越高，微电子电路越多，就越怕电磁干扰。而在汽车上有许多灯具和电器件，尤其是功率较大的前照灯、空调电机和雨刮器电机在开关时会产生浪涌电流，使机械式开关触点产生电弧，产生较大的电磁干扰信号。采用功率霍尔开关电路可以减小这些现象。 霍尔器件通过检测磁场变化，转变为电信号输出，可用于监视和测量汽车各部件运行参数的变化。例如位置、位移、角度、角速度、转速等等，并可将这些变量进行二次变换；可测量压力、质量、液位、流速、流量等。霍尔器件输出量直接与电控单元接口，可实现自动检测。目前的霍尔器件都可承受一定的振动，可在零下40摄氏度到零上150摄氏度范围内工作，全部密封不受水油污染，完全能够适应汽车的恶劣工作环境。 编辑本段发展美国物理学家霍尔(Hall,Edwin Herbert,1855-1938)于1879年在实验中发现，当电流垂直于外磁场通过导体时，在导体的垂直于磁场和电流方向的两个端面之间会出现电势差，这一现象便是霍尔效应。这个电势差也被叫做霍尔电势差。 在霍尔效应发现约100年后，德国物理学家克利青(Klaus von Klitzing, 1943-)等在研究极低温度和强磁场中的半导体时发现了量子霍耳效应，这是当代凝聚态物理学令人惊异的进展之一，克利青为此获得了1985年的诺贝尔物理学奖。 之后，美籍华裔物理学家崔琦(Daniel Chee Tsui,1939- )和美国物理学家劳克林(Robert B.Laughlin，1950-)、施特默(Horst L. St rmer，1949-)在更强磁场下研究量子霍尔效应时发现了分数量子霍尔效应，这个发现使人们对量子现象的认识更进一步，他们为此获得了1998年的诺贝尔物理学奖。 最近，复旦校友、斯坦福教授张首晟与母校合作开展了“量子自旋霍尔效应”的研究。“量子自旋霍尔效应”最先由张首晟教授预言，之后被实验证实。这一成果是美国科学杂志评出的2007年十大科学进展之一。如果这一效应在室温下工作，它可能导致新的低功率的“自旋电子学”计算设备的产生。 目前工业上应用的高精度的电压和电流型传感器有很多就是根据霍尔效应制成的,误差精度能达到0.1%以下本设计中所使用的霍尔传感器 信号原理图外形霍尔传感器3144芯片简介3141 THRU3144SENSITIVE HALL-EFFECT SWITCHES FOR HIGH-TEMPERATURE OPERATIONXVCCSUPPLYGROUNDOUTPUT1 23Dwg. PH-003AThese Hall-effect switches are monolithic integrated circuits with tighter magnetic specifications, designed to operate continuously over extended temperatures to +150C, and are more stable with both temperature and supply voltage changes. The unipolar switching characteristic makes these devices ideal for use with a simple bar or rod magnet. The four basic devices (3141, 3142, 3143, and 3144) are identical except for magnetic switch points.Each device includes a voltage regulator for operation with supply voltages of 4.5 to 24 volts, reverse battery protection diode, quadratic Hall-voltage generator, temperature compensation circuitry, small- signal amplifier, Schmitt trigger, and an open-collector output to sink up to 25 mA. With suitable output pull up, they can be used with bipolar or CMOS logic circuits. The A3141 and A3142 are im- proved replacements for the UGN/UGS3140; the A3144 is the improved replacement for the UGN/UGS3120.The first character of the part number suffix determines the device operating temperature range. Suffix E is for the automotive and industrial temperature range of -40C to +85C. Suffix L is for the automotive and military temperature range of -40C to +150C. Three package styles provide a magnetically optimized package for most applications. Suffix LT is a miniature SOT-89/TO-243AA transis- tor package for surface-mount applications; suffix U is a three-lead plastic mini-SIP, while suffix UA is a three-lead ultra-mini-SIP.Pinning is shown viewed from branded side.ABSOLUTE MAXIMUM RATINGSat TA = +25CSupply Voltage, VCC . 28 V Reverse Battery Voltage, VRCC . -35 V Magnetic Flux Density, B . UnlimitedOutput OFF Voltage, VOUT . 28 V Reverse Output Voltage, VOUT . -0.5 V Continuous Output Current, IOUT . 25 mA Operating Temperature Range, TASuffix E . -40C to +85CSuffix L . -40C to +150CStorage Temperature Range,TS . -65C to +170CFEATURES and BENEFITS Superior Temp. Stability for Automotive or Industrial Applications 4.5 V to 24 V Operation Needs Only An Unregulated Supply Open-Collector 25 mA Output Compatible with Digital Logic Reverse Battery Protection Activate with Small, Commercially Available Permanent Magnets Solid-State Reliability Small Size Resistant to Physical StressAlways order by complete part number, e.g., A3141ELT .Data Sheet27621.6AFUNCTIONAL BLOCK DIAGRAM1 VCCREG.X 3 OUTPUT2 GROUNDDwg. FH-005-2ELECTRICAL CHARACTERISTICS at VCC = 8 V over operating temperature range.CharacteristicSymbolTest ConditionsLimitsMin.Typ.Max.UnitsSupply VoltageVCCOperating4.524VOutput Saturation VoltageVOUT(SAT)IOUT = 20 mA, B BOP175400mVOutput Leakage CurrentIOFFVOUT = 24 V, B BRP1.0 10ASupply CurrentICCB BRP (Output OFF)4.49.mAOutput Rise TimetrRL = 820 , CL = 20 pF0.042.0sOutput Fall TimetfRL = 820 , CL = 20 pF0.182.0sMAGNETIC CHARACTERISTICS in gauss over operating supply voltage range.CharacteristicPart Numbers*A3141A3142A3143A3144Min.Typ. Max.Min. Typ.Max.Min. Typ.Max.Min. Typ. Max.BOPat TA = 25C50100 160130180 230220280 34070350over operating temp. range3010017511518024520528035535450BRPat TA = 25C10 451307512517516522528550330over operating temp. range10451456012519015022530025430Bhysat TA = 25C20 55803055803055802055over operating temp. range2055803055803055802055NOTES: Typical values are at TA = +25C and VCC = 8 V.BOP = operate point (output turns ON); BRP = release point (output turns OFF); Bhys = hysteresis (BOP - BRP).*Complete part number includes a suffix to identify operating temperature range (E- or L-) and package type ( -LT, -U, or -UA).3141 THRU 3144SENSITIVE HALL-EFFECT SWITCHES FOR HIGH-TEMP. OPERATIONTYPICAL OPERATING CHARACTERISTICSA3142 SWITCH POINTSOUTPUT SATURATION VOLTAGE400300300V = 8 VCCI OUT = 20 mA V CC = 4.524 VSATURATION VOLTAGE IN mV200200OPERATE POINTSWITCH POINT IN GAUSS100RELEASE POINT1000-50-25 025 5075 1001251500-50-250 25 50 75 100125150AMBIENT TEMPERATURE IN CDwg. GH-044AMBIENT TEMPERATURE IN CDwg. GH-040-1SUPPLY CURRENTSUPPLY CURRENT107.08.0SUPPLY CURRENT IN mA6.04.02.0B B OPB BRPTA = +25CSUPPLY CURRENT IN mA6.05.04.0B B OPVCC = 8 VB BRP00 5 10 15 20 25SUPPLY VOLTAGE IN VOLTS-50-250255075100AMBIENT TEMPERATURE IN C125150Dwg. GH-041-1Dwg. GH-039-1* Complete part number includes a suffix denoting operating temperature range (E- or L-) and package type ( -LT, -U, or -UA).SENSOR LOCATIONS(0.005” 0.13 mm die placement)Suffix “LT”ACTIVE AREA DEPTHTYPICAL OPERATING CHARACTERISTICS (cont.)CHANGE IN OPERATE POINT200.0300.76 mmNOMA 0.089 2.26 mmCHANGE IN OPERATE POINT IN GAUSS150.0431.09 mm10TA = +25C1235.0Suffix “U”Dwg. MH-008-2C0ACTIVE AREA DEPTH0.0160.41 mmNOM0.0912.31 mm-5.00510152025SUPPLY VOLTAGE IN VOLTS0.0701.78 mmDwg. GH-042-1ABRANDEDSURFACE123Dwg. MH-002-2BOPERATIONThe output of these devices (pin 3) switches low when the magnetic field at the Hall sensor exceeds the operate point threshold (BOP). At this point, the output voltage is VOUT(SAT). When the magnetic field is reduced to below the release point threshold (BRP), the device output goes high. The difference in the magnetic operate and release points is called the hysteresis (Bhys) of the device. This built-in hysteresis allows clean switching of the output even inSuffix “UA”the presence of external mechanical vibration and electrical noise.ACTIVE AREA DEPTH0.0190.48 mmANOM 0.082 2.07 mm0.0551.39 mmBRANDEDSURFACE 1 2 3Dwg. MH-011-10PACKAGE DESIGNATOR LT(SOT-89/TO-243AA)Dimensions in Inches(for reference only)0.1730.0640.0720.0550.0140.0170.1550.1671 2 30.0900.1020.0840.0900.0350.0470.059BSC0.118BSC0.0140.0190.0170.022Dwg. MA-009-3 inDimensions in Millimeters(controlling dimensions)4.401.621.831.400.350.443.944.251 2 32.292.602.132.290.891.201.50BSC3.00BSC0.440.560.360.48Dwg. MA-009-3 mmNOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line).2. Exact body and lead configuration at vendors option within limits shown.3. Height does not include mold gate flash.PACKAGE DESIGNATOR UDimensions in InchesDimensions in Millimeters(controlling dimensions)(for reference only)0.1830.1784.654.520.0630.0591.601.500.1810.1764.604.4745450.086MAX0.6000.5601230.0180.0152.18MAX15.2414.231230.460.38SEE NOTE0.016SEE NOTE0.410.0500.100Dwg. MH-003D in1.272.54Dwg. MH-003D mmDevices in the U package areNOT RECOMMENDED FOR NEW DESIGNNOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line).2. Exact body and lead configuration at vendors option within limits shown.3. Height does not include mold gate flash.4. Recommended minimum PWB hole diameter to clear transition area is 0.035 (0.89 mm).PACKAGE DESIGNATOR UADimensions in InchesDimensions in Millimeters(controlling dimensions)(for reference only)0.1640.1594.174.04450.0620.058451.571.470.1220.117453.102.97450.085MAX1 2 30.0312.16MAX1 2 30.790.6400.6000.01516.2615.240.38SEE NOTE 0.016SEE NOTE 0.41 0.050 BSCDwg. MH-014D in 1.27 BSCDwg. MH-014D mmNOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line).2. Exact body and lead configuration at vendors option within limits shown.3. Height does not include mold gate flash.Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products.The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.HALL-EFFECT SENSORS SELECTION GUIDEPartial PartAvail. Oper.NumberTemp.Characteristics at TA = +25CBOP(max)BRP(min)Bhys(typ)FeaturesNotesHALL-EFFECT UNIPOLAR SWITCHES in order of BOP and Bhys3240 E/L+50+5.010chopper stabilized13210 E705.0 7.7micropower, chopper stabilized3361E+120 +505.0*2-wire, chopper stabilized3362E+120 +505.0*2-wire, chopper stabilized3161E+160 +30202-wire3141E/L+160 +10553235S+175+2515*output 12-25-17515*output 225140E+200+5055300 mA output1, 33142E/L+230 +75553143E/L+340 +165553144E/L+350 +50553122E/L+400+1401053123E/L+440 +1801053121E/L+450 +1