7106芯片资料
ICL7106数字电压表电路及组装要点
ICL7106数字电压表电路及组装要点数字电压表是当前电子、电工、仪器、仪表和测量领域大量使用的一种基本测量工具。
有关数字电压表的书籍和应用已经非常普及了。
这里展示的一份由 ICL7106 A/D 转换电路组成的数字电压表电路，就是一款最通用和最基本的电路。
ICL7106是美国Intersil公司专为数字仪表生产的数字仪，满幅输入电压一般取200mV 或2V。
该芯片集成度高,转换精度高,抗干扰能力强,输出可直接驱动LCD液晶数码管,只需要很少的外部元件,就可以构成数字仪表模块。
一、ICL7106简介1. ICL7106的性能特点（1）＋7V～＋15V单电源供电，可选9V叠层电池，有助于实现仪表的小型化。
低功耗（约16mW），一节9V叠层电池能连续工作200小时或间断使用半年左右。
（2）输入阻抗高（1010Ω）。
内设时钟电路、＋2.8V基准电压源、异或门输出电路，能直接驱动3½位LCD显示器。
（3）属于双积分式A/D转换器，A/D转换准确度达±0.05％，转换速率通常选2次／秒～5次／秒。
具有自动调零、自动判定极性等功能。
通过对芯片的功能检查，可迅速判定其质量好坏。
（4）外围电路简单，仅需配5只电阻、5只电容和LCD显示器，即可构成一块DVM。
其抗干扰能力强，可靠性高。
2. ICL7106的工作原理ICL7106内部包括模拟电路和数字电路两大部分，二者是互相联系的。
一方面由控制逻辑产生控制信号，按规定时序将多路模拟开关接通或断开，保证A/D 转换正常进行；另一方面模拟电路中的比较器输出信号又控制着数字电路的工作状态和显示结果。
下面介绍各部分的工作原理。
（1）模拟电路模拟电路由双积分式A/D转换器构成，其电路如图1所示。
图1主要包括2.8V 基准电压源（E 0）、缓冲器（A 1）、积分器（A 2）、比较器（A 3）和模拟开关等组成。
缓冲器A 4专门用来提高COM 端带负载的能力，可谓设计数字多用表的电阻挡、二极管挡和h FE 挡提供便利条件。
7106中文资料
UTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.3QW-R502-018,BABSOLUTE MAXIMUM RATINGS (Ta=25℃) PARAMETER SYMBOL RATINGS UNITSupply Voltage (V+ ~ V-)V DD 15 VAnalog Input Voltage (Either Input) (Note 1) V I,ANG V+ ~ V- V Reference Input Voltage (Either Input) V I,REF V+ ~ V- VOperating Temperature RangeT OP 0 ~ +70℃THERMAL INFORMATIONPARAMETER SYMBOLRATINGS UNITThermal Resistance (Tyical, Note 2)DIP-40QFP-44θJA5075(°C/W)Maximum Junction Temperature T J 150 °CMaximum Storage Temperature Range T STG -65 ~ +150 °C Maximum Lead Temperature (Soldering 10s) (QFP-44 only) T LOAD 300 °C Note 1: Input voltages may exceed the supply voltages provided the input current is limited to ±100μA.Note 2: θJA is measured with the component mounted on a low effective thermal conductivity test board in free air.See Tech Brief TB379 for details.ELECTRICAL CHARACTERISTICS (Note 3)PARAMETER SYMBOLTEST CONDITIONS MIN TYP MAX UNIT SYSTEM PERFORMANCE Zero Input ReadingR ZV IN =0.0V, Full Scale=200mV-000.0±000.0 +000.0DigitalReading Ratiometric Reading R R V IN =V REF , V REF =100mV 999 999/1000 1000DigitalReadingRollover Error E R -V IN =+V IN ≒200mVDifference in Reading forEqual Positive and Negative Inputs Near Full Scale ±0.2 ±1 CountsLinearity L Full Scale=200mV or Full Scale=2V Maximum Devi-ation from Best Straight Line Fit (Note 5)±0.2±1 CountsCommon Mode Rejection Ratio CMRR V CM =1V,V IN =0V,Full Scale=200mV(Note 5) 50μV/V Noise V N V IN =0V,Full Scale=200mV(Peak-To-Peak Value Not Exceeded 95% of Time)15μV Leakage Current Input I L V IN =0(Note 5) 1 10 pAZero Reading Drift D ZR V IN =0, 0℃ ~ 70℃ (Note 5) 0.2 1 μV/℃ Scale Factor TemperatureCoefficientΦT,S V IN =199mV, 0℃ ~ 70℃, (Ext.Ref.0ppm/℃) (Note 5) 1 5ppm/℃ End Power Supply Character V+Supply CurrentI EPV IN =1.0 1.8 mACOMMON Pin Analog CommonVoltage V COM 25k Ω Between Common and Positive Supply (With Respect to +Supply) 2.4 3.0 3.2 VUTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.4QW-R502-018,BPARAMETER SYMBOLTEST CONDITIONS MIN TYP MAX UNIT Temperature Coefficient of Analog CommonΦT,A25k Ω Between Common and Positive Supply (With Respect to +Supply)80ppm/℃ DISPLAY DRIVERPeak-To-Peak Segment Drive VoltagePeak-To-Peak Backplane Drive VoltageV D,PP V+ ~ V-=9V(Note 4) 4 5.5 6 V Note 3: Unless otherwise noted, specifications apply to the UTC 7106 at T a =25℃, f CLOCK =48kHz, UTC 7106 is tested in the circuit of Figure 1.Note 4: Back plane drive is in phase with segment drive for”off”segment,180 degrees out of phase for”on” segment .Frequency is 20 times conversion rate. Average DC component is less than 50mV. Note 5: Not tested, guaranteed by design.TYPICAL APPLICATIONS AND TEST CIRCUITS(LCD DISPLAY COMPONENTS SELECTED FOR 200mV FULL SCALE)C1=0.1μF C2=0.47μF C3=0.22μF C4=100pF C5=0.02μF R1=24k ΩR2=47k ΩR3=91k ΩR4=1k ΩR5=1M ΩDESIGN INFORMATION SUMMARY SHEET*OSCILLATOR FREQUENCY fosc=0.45/RCC OSC >50pF, R OSC >50k Ω f OSC (Typ)=48kHz*OSCILLATOR PERIOD t OSC =RC/0.45*INTEGRATION CLOCK FREQUENCYUTC 7106CMOS IC f CLOCK=f OSC/4*INTEGRATION PERIODt INT=1000×(4/f OSC)*60/50Hz REJECTION CRITERIONt INT/t60Hz or t INT/t50Hz=Integer*OPTIMUM INTEGRATION CURRENTI INT=4μA*FULL SCALE ANALOG INPUT VOLTAGEV INFS (Typ)=200mV or 2V*INTEGRATE ESISTORR INT= V INFS/ I INT*INTEGRATE CAPACITORC INT=(t INT)(I INT)/ V INT*INTEGRATOR OUTPUT VOLTAGE SWINGV INT=(t INT)(I INT)/ C INT*VINT MAXIMUM SWING(V- + 0.5V)<V INT<(V+ - 0.5V), V INT (Typ)=2V*DISPLAY COUNTCOUNT=1000×V IN/V REF*CONVERSION CYCLEt CYC=t CLOCK×4000t CYC=t OSC×16,000When f OSC=48kHz, t CYC=333ms*COMMON MODE INPUT VOLTAGE(V- + 1V)<V IN<(V+ - 0.5V)*AUTO-ZERO CAPACITOR0.01μF<C AZ<1μF*REFERENCE CAPACITOR0.1μF<C REF<1μF*V COMBiased between Vi and V-*V COM≒V+ - 2.8VRegulation lost when V+ to V- <≒6.8VIf V COM is externally pulled down to (V+ to V-)/2, the V COM circuit will turn off.*POWER SUPPLY: SINGLE 9VV+ - V- =9VUTC UNISONIC TECHNOLOGIES CO., LTD. 5QW-R502-018,BUTC 7106CMOS IC V GND≒V+ - 4.5VDigital supply is generated by internal parts.*DISPLAY: LCDType: Direct drive with digital logic supply amplitude.TYPICAL INTEGRATOR AMPLIFIER OUTPUT WAVEFORM (INT PIN)TOTAL CONVERSION TIME=4000 × t CLOCK=16,000 × toscDETAILED DESCRIPTIONANALOG SECTIONFigure 1 shows the Analog Section for the UTC 7106. Each measurement cycle is divided into three phases. They are(1) auto-zero(A-Z), (2)signal integrate (INT)and (3)de-integrate(DE).AUTO-ZERO PHASEDuring auto-zero three things happen. First, input high and low are disconnected from the pins and internally shorted to analog COMMON. Second, the reference capacitor is charged to the reference voltage. Third, a feedback loop is closed around the system to charge the auto-zero capacitor C AZ to compensate for offset voltages in the buffer amplifier, integrator, and comparator. Since the comparator is included in the loop, the A-Z accuracy is limited only by the noise of the system. In any case. the offset referred to the input is less than 10μV.SIGNAL INTEGRATE PHASEDuring signal integrate, the auto-zero loop is opened, the internal short is removed, and the internal input high and low are connected to the external pins. The converter then integrates the differential voltage between IN HI and IN LO for a fixed time. This differential voltage can be within a wide common mode range: up to 1V from either supply. if, on the other hand, the input signal has no return with respect to the converter power supply, IN LO can be tied to analog COMMON to establish the correct common mode voltage. At the end of this phase, the polarity of the integrated signal is determined.DE-INTEGRATE PHASEThe final phase is de-integrate, or reference integrate. Input low is internally connected to analog COMMON and input high is connected across the previously charged reference capacitor. Circuitry within the chip ensures that the capacitor will be connected with the correct polarity to cause the integrator output to return to zero. The time required for the output to return to zero is proportional to the input signal. Specifically the digital reading displayed is: DISPLAY COUNT=1000( V IN/ V REF ).DIFFERENTIAL INPUTThe input can accept differential voltages anywhere within the common mode range of the input amplifier, or specifically from 0.5V below the positive supply to 1V above the negative supply. In this range, the system has a CMRR of 86dB typical. However, care must be exercised to assure the integrator output does not saturate. A worst UTC UNISONIC TECHNOLOGIES CO., LTD. 6QW-R502-018,BUTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.7QW-R502-018,Bcase condition would be a large positive common mode voltage with a near full scale negative differential input voltage. The negative input signal drives the integrator positive when most of its swing has been used up by the positive common mode voltage. For these critical applications the integrator output swing can be reduced to less than the recommended 2V full scale swing with little loss of accuracy. The integrator output can swing to within 0.3V of either supply without loss of linearity.DIFFERENTIAL REFERENCEThe reference voltage can be generated anywhere within the power supply voltage of the converter. The main source of common mode error is a roll-over voltage caused by the reference capacitor losing or gaining charge to stray capacity on its nodes. If there is a large common mode voltage, the reference capacitor can gain charge (increase voltage) when called up to de-integrate a positive signal but lose charge (decrease voltage) when called up to de-integrate a negative input signal. This difference in reference for positive or negative input voltage will give a roll-over error. However, by selecting the reference capacitor such that it is large enough in comparison to the straycapacitance, this error can be held to less than 0.5 count worst case. (See Component Value Selection)COMMONIN LOFIGURE 1. ANALOG SECTIONIN HIANALOG COMMONThis pin is included primarily to set the common mode voltage for battery operation (UTC 7106) or for any system where the input signals are floating with respect to the power supply. The COMMON pin sets a voltage that is approximately 2.8V more negative than the positive supply. This is selected to give a minimum end-of-life battery voltage of about 6V. However, analog COMMON has some of the attributes of a reference voltage. When the total supply voltage is large enough to cause the zener to regulate(>7V), the COMMON voltage will have a low voltage coefficient (0.001%/V), low output impedance (≒15Ω), and a temperature coefficient typically less than 80ppm/℃. The UTC 7106, with its negligible dissipation, suffers from none of these problems. In either case, an external reference can easily be added, as shown in Figure 1.Analog COMMON is also used as the input low return during auto-zero and de-integrate. If IN LO is different from analog COMMON, a common mode voltage exists in the system and is taken care of by the excellent CMRR of the converter. However, in some applications IN LO will be set at a fixed known voltage(power supply common for instance).In this application, analog COMMON should be tied to the same point, thus removing the common mode voltage from the converter. The same holds true for the reference voltage. If reference can be conveniently tied to analog COMMON, it should be since this removes the common mode voltage from the reference system.Within the IC, analog COMMON is tied to an N-Channel FET that can sink approximately 30mA of current to hold the voltage 2.8V below the positive supply (when a load is trying to pull the common line positive). However, there isUTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.8QW-R502-018,Bonly 10μA of source current, so COMMON may easily be tied to a more negative voltage thus overriding the internalreference.FIGURE 2B.FIGURE 2A.FIGURE 2. USING AN EXTERNAL REFERENCETESTThe TEST pin serves two function. On the UTC 7106 it is coupled to the internally generated digital supply through a 500Ω resistor. Thus it can be used as the negative supply for externally generated segment drivers such as decimal points or any other presentation the user may want to include on the LCD display. Figures 3 and 4 show such an application. No more than a 1mA load should be applied.The second function is a “lamp test”. When TEST is pulled high (to V+) all segments will be turned on and the display should read ”1888”. The TEST pin will sink about 15mA under these conditions.CAUTION: In the lamp test mode, the segments have a constant DC voltage (no square-wave) . This may burn the LCD display if maintained for extended periods.FIGURE 3. SIMPLE INVERTER FOR FIXED DECIMAL POINTTO LCD DECIMAL POINTSFIGURE 4. EXCLUSIVE "OR" GATE FORDECIMAL POINT DRIVEDIGITAL SECTIONFigure 5 show the digital section for the UTC 7106, respectively. In the UTC 7106, an internal digital ground is generated from a 6V Zener diode and a large P-Channel source follower. This supply is made stiff to absorb the relative large capacitive currents when the back plane(BP) voltage is switchied. The BP frequency is the clock frequency divided by 800. For three readings/sec, this is a 60Hz square wave with a nominal amplitude of 5V. TheUTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.9QW-R502-018,Bsegments are driven at the same frequency and amplitude and are in phase with BP when OFF, but out of phase when ON. In all cases negligible DC voltage exists across the segments.FIGURE 5. DIGITAL SECTIONTESTV-V+SYSTEM TIMINGFigure 6 shows the clocking arrangement used in the UTC 7106. Two basic clocking arrangements can be used: 1. Figure 6A. An external oscillator connected to pin 40. 2. Figure 6B. An R-C oscillator using all three pins.The oscillator frequency is divided by four before it clocks the decade counters. It is then further divided to form the three convert-cycle phases. These are signal integrate (1000 counts), reference de-integrate(0 to 2000 counts) and auto-zero(1000 ~ 3000 counts). For signals less than full scale. auto-zero gets the unused portion of reference de-integrate. This makes a complete measure cycle of 4,000 counts (16,000 clock pulses) independent of input voltage. For three readings/second, an oscillator frequency of 48kHz would be used.To achieve maximum rejection of 60Hz pickup, the signal integrate cycle should be a multiple of 60Hz. Oscillator frequencies of 240kHz, 120kHz, 80kHz, 60kHz, 48kHz, 40kHz, 33 1/3kHz, etc should be selected. For 50Hz rejection, Oscillator frequencies of 200kHz, 100kHz, 66 2/3kHz, 50kHz, 40kHz, etc would be suitable. Note that 40kHz (2.5 readings/second) will reject both 50Hz and 60Hz (also 400Hz and 440Hz).UTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.10QW-R502-018,BFIGURE 6AFIGURE 6BFIGURE 6. CLOCK CIRCUITSCOMPONENT VALUE SELECTION Integrating ResistorBoth the buffer amplifier and the integrator have a class A output stage with 100μA of quiescent current. They can supply 4μA of drive current with negligible nonlinearity. The integrating resistor should be large enough toremain in this very linear region over the input voltage range, but small enough that undue leakage requirements are not placed on the PC board. For 2V full scale, 470k Ω is near optimum and similarly a 47k Ω for a 200mV scale.Integrating CapacitorThe integrating capacitor should be selected to give the maximum voltage swing that ensures tolerance buildup will not saturate the integrator swing(approximately. 0.3V from either supply).In the UTC 7106, when the analogCOMMON is used as a reference, a nominal+2V fullscale integrator swing is fine. For three readings/second (48kHz clock) nominal values for C INT are 0.22μF and 0.10μF, respectively. Of course, if different oscillator frequencies are used, these values should be changed in inverse proportion to maintain the same output swing.An additional requirement of the integrating capacitor is that it must have a low dielectric absorptiont to prevent roll-over errors. While other types of capacitors are adequate for this application, polypropylene capacitors give undetectable errors at reasonable cost.Auto-Zero CapacitorThe size of the auto-zero capacitor has some influence on the noise of the system. For 200mV full scale where noise is very important, a 0.47μF capacitor is recommended. On the 2V scale, a 0.047μF capacitor increases the speed of recovery from overload and is adequate for noise on this scale.Reference CapacitorA 0.1μF capacitor gives good results in most applications. However, where a large common mode voltage exists (i.e.,the REF LO pin is not at analog COMMON)and a 200mV scale is used, a larger value is required to prevent roll-ovre error. Generally 1μF will hold the roll-over error to 0.5 count in this instance.Oscillator ComponentsFor all ranges of frequency a 91k Ω resistor is recommended and the capacitor is selected from the equation: f= 0.45/RC For 48kHz Clock (3 Readings/sec), C=100pF.Reference VoltageThe analog input required to generate full scale output (2000 counts) is: V IN =2V REF .Thus, for the 200mV and 2V scale, V REF should equal 100mV and 1V, respectively.However,in many applications where the A/D is connected to a transducer, there will exist a scale factor other than unity between the input voltage and the digital reading. For instance, in a weighing system, the designer might like to have a full scale reading when the voltage from theUTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.11QW-R502-018,Btransducer is 0.662V. Instead of dividing the input down to 200mV, the designer should use the input voltage directly and select V REF =0.341V. Suitable values for integrating resistor and capacitor would be 120k Ω and 0.22μF. This makes the system slightly quieter and also avoids a divider network on the input.TYPICAL APPICATIONSThe UTC 7106 may be used in a wide variety of configurations. The circuits which follow show some of the possibilities, and serve to illustrate the exceptional versatility of these A/D converters.9V INValues shown are for 200mV full scale,3 readings/sec.,floating supply voltage(9V battery).FIGURE 7. USING THE INTERNAL REFERENCEUTC 7106 CMOS ICUTC UNISONIC TECHNOLOGIES CO., LTD.12QW-R502-018,BTYPICAL APPLICATIONS (Continued)INFIGURE 8. RECOMMENDED COMPONENT VALUES FOR 2V FULL SCALEV-UTC 7106CMOS IC TYPICAL APPLICATIONS (Continued)A sillicon diode-connected transistor has a temperature coefficient of about -2mV/ ℃.Calibration is achieved by placing the sensing transistor in ice water and adjusting thezeroing potentiometer for a 000.0 reading.The sensor should then be placed in boilingwater and the scale-factor potentiometer adjusted for a 100.0 readingFIGURE 9. USED AS A DIGITAL CENTIGRADE THERMOMETER UTC UNISONIC TECHNOLOGIES CO., LTD. 13QW-R502-018,BUTC 7106CMOS IC TYPICAL APPLICATIONS (Continued)CD4077FIGURE 10. CIRCUIT FOR DEVELOPING UNDERRANGE ANDOVERRANGE SIGNAL FROM UTC 7106 OUTPUTSUTC UNISONIC TECHNOLOGIES CO., LTD. 14QW-R502-018,BUTC 7106CMOS IC TYPICAL APPLICATIONS (Continued)Test is used as a common-mode reference level to ensure compatiblity with most op amps.FIGURE 11. AC TO DC CONVERTER WITH UTC 7106UTC UNISONIC TECHNOLOGIES CO., LTD. 15QW-R502-018,B。
icl7106驱动液晶屏原理 -回复
icl7106驱动液晶屏原理-回复题目：ICL7106驱动液晶屏原理摘要：本文将详细介绍ICL7106驱动液晶屏的原理。
首先，将介绍ICL7106芯片的结构和功能。
接下来，将解释液晶屏的基本原理和工作方式。
然后，将阐述ICL7106如何驱动液晶屏实现显示功能。
最后，将讨论液晶屏驱动的一些注意事项和常见问题。
1.引言ICL7106是一种常用的专用集成电路芯片，特别适用于液晶屏的驱动。
通过驱动液晶屏，ICL7106可以将数字信号转换为人们可以读取和理解的图形、数字或字母等形式，广泛应用于电子仪器、仪表、计量设备等领域。
2.ICL7106芯片的结构与功能ICL7106芯片是一种模拟电路集成电路，包括模数转换器、显示驱动器、参考电压源等功能模块。
它具有高稳定性、低功耗、高精度等特点。
2.1 模数转换器模数转换器是ICL7106的核心模块，它可以将模拟信号转换为数字信号。
ICL7106芯片内部集成了一个双积分式A/D转换器，通过精确的电压比较和积分测量，将输入信号转换为数字量。
2.2 显示驱动器ICL7106具有多种显示模式，可以驱动不同类型和不同大小的液晶屏，如7段LED、16段LED、点阵等。
同时，它支持多种显示方式，如数字表示、字母表示、符号表示等，可根据需要显示不同的信息。
2.3 参考电压源ICL7106芯片内部集成了一个高稳定的参考电压源，用于提供稳定的参考电压给模数转换器，确保转换的准确性和精度。
3.液晶屏的基本原理和工作方式液晶屏是一种基于液晶显示原理的显示设备。
液晶是一种特殊的有机化合物，具有有机光电特性。
液晶显示屏通过控制液晶分子的排列状态来实现显示。
液晶显示屏的原理是利用液晶的电光效应和光学各向异性效应。
当施加电场或改变电压时，液晶分子的排列状态发生变化，从而改变了通过液晶的光的偏振状态，实现显示效果。
4.ICL7106如何驱动液晶屏实现显示功能ICL7106芯片将转换得到的数字信号通过显示驱动器模块发送给液晶屏。
7106芯片资料
自动校 零阶段
正向积分阶段
反向积分阶段
3 2
1 1000计数
1000～3000个
T1
计数脉冲
1000计数脉冲
T2 T2
0～2000个计数脉冲
7106芯片工作时钟周期分配示意图
模拟电路和数字电路都集成在一 块大规模集成电路——7106芯片上。
第三章 万用表的电路原理及装配
3.1万用表的基本结构：
3.1.4 液晶显示概述 数字万用表的液晶显示器是采用段电极显
示的方式来实现的，也就是液晶显示器的前部 电极被分割成a,b,c,d,e,f,g七段，各段电极 a,b,c,d,e,f,g与“7106”集成电路芯片中的 “BP”引脚，也叫背电极。背电极也是前部电 极的共用电极。若是各段前部电极与背电极之 间电位相等时，则液晶不显示。若某一段或几 段前部电极与背电极存在电位差时，则液晶显 示。这样就可以根据被测参数的实际情况分别 显示十进制中的1，2，3，4，5，6，7，8， 9，0这十个数。
第三章 万用表的电路原理及装配
3.2双积分A/D转换器的工作
原理
3.2.1 A/D转换器循环过程：
积分电压
3.反向积分
VINT
正向积分结束时逻辑控制电路断
开Kin开关，并根据比较器输出电压的 极性作出判定后，将在自动调零阶段
已经对基准电容CREF充好的基准电压 极性相反地送入积分器，进行反向积
分，经过时间T2积分器的输出又回到
14 G1
一般规定为7～15V，常选用9V叠层电
E1 15
池，消耗电流仅为1.8mA，功耗仅为
数字电压表电路7106和7107
数字电压表电路ICL7107ICL7107.7106pdf资料下载ICL7107 安装电压表头时的一些要点：按照测量＝±199.9mV 来说明。
1.辨认引脚：芯片的第一脚，是正放芯片，面对型号字符，然后，在芯片的左下方为第一脚。
也可以把芯片的缺口朝左放置，左下角也就是第一脚了。
许多厂家会在第一脚旁边打上一个小圆点作为标记。
知道了第一脚之后，按照反时针方向去走，依次是第 2 至第 40 引脚。
（1 脚与 40 脚遥遥相对）。
2.牢记关键点的电压：芯片第一脚是供电，正确电压是 DC5V 。
第 36 脚是基准电压，正确数值是 100mV，第 26 引脚是负电源引脚，正确电压数值是负的，在 －3V 至 －5V 都认为正常，但是不能是正电压，也不能是零电压。
芯片第 31 引脚是信号输入引脚，可以输入 ±199.9mV 的电压。
在一开始，可以把它接地，造成“0”信号输入，以方便测试。
3.注意芯片 27,28,29 引脚的元件数值，它们是 0.22uF,47K,0.47uF 阻容网络，这三个元件属于芯片工作的积分网络，不能使用磁片电容。
芯片的 33 和 34 脚接的 104 电容也不能使用磁片电容。
4.注意接地引脚：芯片的电源地是 21 脚，模拟地是 32 脚，信号地是 30 脚，基准地是 35 脚，通常使用情况下，这 4 个引脚都接地，在一些有特殊要求的应用中（例如测量电阻或者比例测量），30 脚或 35 脚就可能不接地而是按照需要接到其他电压上。
－－ 本文不讨论特殊要求应用。
5.负电压产生电路：负电压电源可以从电路外部直接使用 7905 等芯片来提供，但是这要求供电需要正负电源，通常采用简单方法，利用一个 +5V 供电就可以解决问题。
比较常用的方法是利用 ICL7660 或者 NE555 等电路来得到，这样需要增加硬件成本。
我们常用一只 NPN 三极管，两只电阻，一个电感来进行信号放大，把芯片 38 脚的振荡信号串接一个 20K －56K 的电阻连接到三极管“B”极，在三极管“C”极串接一个电阻（为了保护）和一个电感（提高交流放大倍数），在正常工作时，三极管的“C”极电压为 2.4V － 2.8V 为最好。
主流AD转换芯片7106学习详解
主流AD转换芯片7106学习详解一、ICL7106介绍 ICL7106是intersil公司推出的一款3½位A/D转换器电压应用芯片,主要用于仪器仪表，能构成3½位液晶显示的数字电压表。
ICL7106是目前广泛应用的一种A/D转换器。
ICL7106引脚封装图二、 ICL7106芯片结构简述 ICL7106是高性能、低功耗的三位半A/D转换电路，具有很强的抗干扰能力。
含有七段译码器、显示驱动器、参考源、时钟系统以及背光电极驱动，可直接驱动LCD。
ICL7106将高精度、通用性和低成本很好的结合在一起，有低于10μA的自动校零功能，零漂小于1μV/℃，低于10pA的输入电流，极性转换误差小于一个字。
真正的差动输入和差动参考源在各种系统中都很有用。
另外，只需用十个左右的无源元件和一个LCD屏就可以构成高性能的仪表面板，实现了低成本和单电源工作。
三、 ICL7106的工作原理 ICL7106 内部包括模拟电路和数字电路两大部分，二者是互相联系的。
一方面由控制逻辑产生控制信号，按规定时序将多路模拟开关接通或断开，保证A/D 转换正常进行；另一方面模拟电路中的比较器输出信号又控制着数字电路的工作状态和显示结果。
下面介绍各部分的工作原理。
（1）模拟电路 模拟电路由双积分式A/D转换器构成。
主要包括2.8V基准电压源（E0）、缓冲器（A1）、积分器（A2）、比较器（A3）和模拟开关等组成。
缓冲器A4专门用来提高COM端带负载的能力，可谓设计数字多用表的电阻挡、二极管挡和hFE挡提供便利条件。
这种转换器具有转换准确度高、抗串模干扰能力强、电路简单、成本低等优点，适合做低速模／数转换。
每个转换周期分三个阶段进行：自动调零（AZ）、正向积分（INT）、反向积分（DE），并按照AZ→INT→DE→AZ…的顺序进行循环。
令计数脉冲的周期为TCP，每个测量周期共需4000TCP。
其中，正向积分时间固定不变，T1＝1000TCP。
TC7106_06资料
TC7106/A/TC7107/AFeatures:•Internal Reference with Low Temperature Drift: -TC7106/7: 80ppm/°C Typical-TC7106A/7A: 20ppm/°C Typical•Drives LCD (TC7106) or LED (TC7107)Display Directly•Zero Reading with Zero Input•Low Noise for Stable Display•Auto-Zero Cycle Eliminates Need for Zero Adjustment•True Polarity Indication for Precision Null Applications•Convenient 9V Battery Operation (TC7106A)•High-Impedance CMOS Differential Inputs: 1012Ω•Differential Reference Inputs Simplify Ratiometric Measurements•Low-Power Operation: 10mW Applications:•Thermometry•Bridge Readouts: Strain Gauges, Load Cells, Null Detectors•Digital Meters: Voltage/Current/Ohms/Power, pH •Digital Scales, Process Monitors•Portable InstrumentationDevice Selection Table General Description:The TC7106A and TC7107A 3-1/2 digit direct displaydrive Analog-to-Digital Converters allow existing 7106/7107 based systems to be upgraded. Each device has a precision reference with a 20ppm/°C max tempera-ture coefficient. This represents a 4 to 7 times improve-ment over similar 3-1/2 digit converters. Existing 7106 and 7107 based systems may be upgraded withoutchanging external passive component values. TheTC7107A drives common anode light emitting diode (LED) displays directly with 8mA per segment. A lowcost, high resolution indicating meter requires only adisplay, four resistors, and four capacitors.The TC7106A low-power drain and 9V battery operationmake it suitable for portable applications.The TC7106A/TC7107A reduces linearity error to lessthan 1 count. Rollover error – the difference in readings for equal magnitude, but opposite polarity input signals,is below ±1 count. High-impedance differential inputsoffer 1pA leakage current and a 1012Ω input imped-ance. The differential reference input allows ratiometricmeasurements for ohms or bridge transducermeasurements. The 15μV P–P noise performance ensures a “rock solid” reading. The auto-zero cycle ensures a zero display reading with a zero volts input.Package Code Package Pin LayoutTemperatureRangeCPI40-Pin PDIP Normal0°C to +70°CIPL40-Pin PDIP Normal-25°C to +85°CIJL40-Pin CERDIP Normal-25°C to +85°CCKW44-Pin PQFP FormedLeads0°C to +70°CCLW44-Pin PLCC —0°C to +70°C3-1/2 Digit Analog-to-Digital Converters© 2006 Microchip Technology Inc.DS21455C-page 1TC7106/A/TC7107/APackage TypeDS21455C-page 2© 2006 Microchip Technology Inc.TC7106/A/TC7107/A Typical Application© 2006 Microchip Technology Inc.DS21455C-page 3TC7106/A/TC7107/ADS21455C-page 4© 2006 Microchip Technology Inc.1.0ELECTRICALCHARACTERISTICSAbsolute Maximum Ratings*TC7106ASupply Voltage (V+ to V-).......................................15V Analog Input Voltage (either Input) (Note 1)...V+ to V-Reference Input Voltage (either Input)............V+ to V-Clock Input...................................................Test to V+Package Power Dissipation (T A ≤ 70°C) (Note 2):40-Pin CERDIP.......................................2.29W 40-Pin PDIP ............................................1.23W 44-Pin PLCC...........................................1.23W 44-Pin PQFP...........................................1.00W Operating Temperature Range:C (Commercial) Devices..............0°C to +70°C I (Industrial) Devices ................-25°C to +85°C Storage Temperature Range..............-65°C to +150°CTC7107ASupply Voltage (V+)...............................................+6V Supply Voltage (V-)..................................................-9V Analog Input Voltage (either Input) (Note 1)...V+ to V-Reference Input Voltage (either Input)............V+ to V-Clock Input..................................................GND to V+Package Power Dissipation (T A ≤ 70°C) (Note 2):40-Pin CERDip........................................2.29W 40-Pin PDIP ............................................1.23W 44-Pin PLCC...........................................1.23W 44-Pin PQFP...........................................1.00W Operating Temperature Range:C (Commercial) Devices..............0°C to +70°C I (Industrial) Devices ................-25°C to +85°C Storage Temperature Range..............-65°C to +150°C*Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability.TC7106/A/TC7107/ATABLE 1-1:TC7106/A AND TC7107/A ELECTRICAL SPECIFICATIONSElectrical Characteristics: Unless otherwise noted, specifications apply to both the TC7106/A and TC7107/A at T A = 25°C,f CLOCK = 48kHz. Parts are tested in the circuit of the Typical Operating Circuit.Symbol Parameter Min Typ Max Unit Test ConditionsZ IR Zero Input Reading-000.0±000.0+000.0DigitalReading V IN = 0.0VFull Scale = 200.0mVRatiometric Reading999999/10001000DigitalReading V IN = V REFV REF = 100mVR/O Rollover Error (Difference in Reading forEqual Positive and NegativeReading Near Full Scale)-1±0.2+1Counts V IN- = + V IN+ ≅ 200mVLinearity (Max. Deviation from Best Straight Line Fit)-1±0.2+1Counts Full Scale = 200mV orFull Scale = 2.000VCMRR Common Mode Rejection Ratio (Note 3)—50—μV/V V CM = ±1V, V IN = 0V,Full Scale = 200.0mVe N Noise (Peak to Peak Value not Exceeded95% of Time)—15—μV V IN = 0VFull Scale - 200.0mVI L Leakage Current at Input—110pA V IN = 0VZero Reading Drift—0.21μV/°C V IN = 0V“C” Device = 0°C to +70°C— 1.02μV/°C V IN = 0V“I” Device = -25°C to +85°C TC SF Scale Factor Temperature Coefficient—15ppm/°C V IN = 199.0mV,“C” Device = 0°C to +70°C(Ext. Ref = 0ppm°C)——20ppm/°C V IN = 199.0mV“I” Device = -25°C to +85°C I DD Supply Current (Does not include LEDCurrent For TC7107/A)—0.8 1.8mA V IN = 0.8V C Analog Common Voltage(with Respect to Positive Supply)2.7 3.05 3.35V25kΩ Between Common andPositive SupplyV CTC Temperature Coefficient of AnalogCommon (with Respect to Positive Supply)————25kΩ Between Common andPositive Supply7106/7/A7106/7208050—ppm/°Cppm/°C0°C ≤ T A≤ +70°C(“C” Commercial TemperatureRange Devices)V CTC Temperature Coefficient of AnalogCommon (with Respect to Positive Supply)——75ppm/°C0°C ≤ T A≤ +70°C(“I” Industrial TemperatureRange Devices)V SD TC7106A ONLY Peak to Peak Segment Drive Voltage 456V V+ to V- = 9V(Note 4)V BD TC7106A ONLY Peak to Peak Backplane Drive Voltage 456V V+ to V- = 9V(Note 4)TC7107A ONLYSegment Sinking Current (Except Pin 19)58.0—mA V+ = 5.0VSegment Voltage = 3VTC7107A ONLYSegment Sinking Current (Pin 19)1016—mA V+ = 5.0VSegment Voltage = 3VNote1:Input voltages may exceed the supply voltages, provided the input current is limited to ±100μA.2:Dissipation rating assumes device is mounted with all leads soldered to printed circuit board.3:Refer to “Differential Input” discussion.4:Backplane drive is in phase with segment drive for “OFF” segment, 180° out of phase for “ON” segment.Frequency is 20 times conversion rate. Average DC component is less than 50mV.© 2006 Microchip Technology Inc.DS21455C-page 5TC7106/A/TC7107/ADS21455C-page 6© 2006 Microchip Technology Inc.2.0PIN DESCRIPTIONSThe descriptions of the pins are listed in Table 2-1.TABLE 2-1:PIN FUNCTION TABLEPin Number (40-Pin PDIP)NormalPin No.(40-Pin PDIP)(ReversedSymbol Description1(40)V+Positive supply voltage.2(39)D 1Activates the D section of the units display.3(38)C 1Activates the C section of the units display.4(37)B 1Activates the B section of the units display.5(36)A 1Activates the A section of the units display.6(35)F 1Activates the F section of the units display.7(34)G 1Activates the G section of the units display.8(33)E 1Activates the E section of the units display.9(32)D 2Activates the D section of the tens display.10(31)C 2Activates the C section of the tens display.11(30)B 2Activates the B section of the tens display.12(29)A 2Activates the A section of the tens display.13(28)F 2Activates the F section of the tens display.14(27)E 2Activates the E section of the tens display.15(26)D 3Activates the D section of the hundreds display.16(25)B 3Activates the B section of the hundreds display.17(24)F 3Activates the F section of the hundreds display.18(23)E 3Activates the E section of the hundreds display.19(22)AB 4Activates both halves of the 1 in the thousands display.20(21)POL Activates the negative polarity display.21(20)BP/GND LCD Backplane drive output (TC7106A). Digital Ground (TC7107A).22(19)G 3Activates the G section of the hundreds display.23(18)A 3Activates the A section of the hundreds display.24(17)C 3Activates the C section of the hundreds display.25(16)G 2Activates the G section of the tens display.26(15)V-Negative power supply voltage.27(14)V INT Integrator output. Connection point for integration capacitor. See INTEGRATING CAPACITOR section for more details.28(13)V BUFF Integration resistor connection. Use a 47k Ω resistor for a 200mV full scale range and a 47k Ω resistor for 2V full scale range.29(12)C AZThe size of the auto-zero capacitor influences system noise. Use a 0.47μF capacitor for 200mV full scale, and a 0.047μF capacitor for 2V full scale. See Section 7.1 “Auto-Zero Capacitor (CAZ)” on Auto-Zero Capacitor for more details.30(11)V IN -The analog LOW input is connected to this pin.31(10)V IN +The analog HIGH input signal is connected to this pin.32(9)ANALOG COMMON This pin is primarily used to set the Analog Common mode voltage for battery opera-tion or in systems where the input signal is referenced to the power supply. It alsoacts as a reference voltage source. See Section 8.3 “Analog Common (Pin 32)” on ANALOG COMMON for more details. 33(8)C REF -See Pin 34.34(7)C REF +A0.1μF capacitor is used in most applications. If a large Common mode voltage exists (for example, the V IN - pin is not at analog common), and a 200mV scale is used, a 1μF capacitor is recommended and will hold the rollover error to 0.5 count.35(6)V REF -See Pin 36.© 2006 Microchip Technology Inc.DS21455C-page 7TC7106/A/TC7107/A36(5)V REF +The analog input required to generate a full scale output (1999 counts). Place 100mV between Pins 35 and 36 for 199.9mV full scale. Place 1V between Pins 35 and 36 for 2V full scale. See paragraph on Reference Voltage.37(4)TESTLamp test. When pulled HIGH (to V+) all segments will be turned on and the display should read -1888. It may also be used as a negative supply for externally generated decimal points. See paragraph under TEST for additional information.38(3)OSC3See Pin 40. 39(2)OSC2See Pin 40.40(1)OSC1Pins 40, 39, 38 make up the oscillator section. For a 48kHz clock (3 readings per section), connect Pin 40 to the junction of a 100k Ω resistor and a 100pF capacitor. The 100k Ω resistor is tied to Pin 39 and the 100pF capacitor is tied to Pin 38.TABLE 2-1:PIN FUNCTION TABLE (CONTINUED)Pin Number (40-Pin PDIP)NormalPin No.(40-Pin PDIP)(ReversedSymbol DescriptionTC7106/A/TC7107/ADS21455C-page 8© 2006 Microchip Technology Inc.3.0DETAILED DESCRIPTION(All Pin designations refer to 40-Pin PDIP .)3.1Dual Slope Conversion PrinciplesThe TC7106A and TC7107A are dual slope, integrating Analog-to-Digital Converters. An understanding of the dual slope conversion technique will aid in following the detailed operation theory.The conventional dual slope converter measurement cycle has two distinct phases:•Input Signal Integration•Reference Voltage Integration (De-integration)The input signal being converted is integrated for a fixed time period (T SI ). Time is measured by counting clock pulses. An opposite polarity constant reference voltage is then integrated until the integrator output voltage returns to zero. The reference integration time is directly proportional to the input signal (T RI ). See Figure 3-1.FIGURE 3-1:Basic Dual Slope ConverterIn a simple dual slope converter, a complete conver-sion requires the integrator output to “ramp-up” and “ramp-down.” A simple mathematical equation relates the input signal, reference voltage and integration time.EQUATION 3-1:For a constant V IN :EQUATION 3-2:The dual slope converter accuracy is unrelated to the integrating resistor and capacitor values as long as they are stable during a measurement cycle. An inher-ent benefit is noise immunity. Noise spikes are integrated or averaged to zero during the integration periods. Integrating ADCs are immune to the large conversion errors that plague successive approxima-tion converters in high noise environments. Interfering signals with frequency components at multiples of the averaging period will be attenuated. Integrating ADCs commonly operate with the signal integration period set to a multiple of the 50/60Hz power line period (see Figure 3-2).FIGURE 3-2:Normal Mode Rejection of Dual Slope Converter1RCV R T RI RCT SIV IN (t)dt =∫Where:V R =Reference voltageT SI =Signal integration time (fixed)T RI =Reference voltage integration time (variable).V IN = V RT RI T SITC7106/A/TC7107/A4.0ANALOG SECTIONIn addition to the basic signal integrate and de-integrate cycles discussed, the circuit incorporates an auto-zero cycle. This cycle removes buffer amplifier, integrator, and comparator offset voltage error terms from the conversion. A true digital zero reading results without adjusting external potentiometers. A complete conversion consists of three cycles: an auto-zero, signal integrate and reference integrate cycle.4.1Auto-Zero CycleDuring the auto-zero cycle, the differential input signal is disconnected from the circuit by opening internal analog gates. The internal nodes are shorted to analog common (ground) to establish a zero input condition. Additional analog gates close a feedback loop around the integrator and comparator. This loop permits comparator offset voltage error compensation. The voltage level established on C AZ compensates for device offset voltages. The offset error referred to the input is less than 10μV.The auto-zero cycle length is 1000 to 3000 counts. 4.2Signal Integrate CycleThe auto-zero loop is entered and the internal differen-tial inputs connect to V IN+ and V IN-. The differential input signal is integrated for a fixed time period. The TC7136/A signal integration period is 1000 clock periods or counts. The externally set clock frequency is divided by four before clocking the internal counters. The integration time period is:EQUATION 4-1:The differential input voltage must be within the device Common mode range when the converter and mea-sured system share the same power supply common (ground). If the converter and measured system do not share the same power supply common, V IN-should be tied to analog common.Polarity is determined at the end of signal integrate phase. The sign bit is a true polarity indication, in that signals less than 1LSB are correctly determined. This allows precision null detection limited only by device noise and auto-zero residual offsets.4.3Reference Integrate PhaseThe third phase is reference integrate or de-integrate. V IN- is internally connected to analog common and V IN+is connected across the previously charged reference capacitor. Circuitry within the chip ensures that the capacitor will be connected with the correct polarity to cause the integrator output to return to zero. The time required for the output to return to zero is proportional to the input signal and is between 0 and 2000 counts.The digital reading displayed is:EQUATION 4-2:5.0DIGITAL SECTION (TC7106A) The TC7106A (Figure5-2) contains all the segment drivers necessary to directly drive a 3-1/2 digit liquid crystal display (LCD). An LCD backplane driver is included. The backplane frequency is the external clock frequency divided by 800. For three conversions/ second, the backplane frequency is 60Hz with a 5V nominal amplitude. When a segment driver is in phase with the backplane signal, the segment is “OFF.” An out of phase segment drive signal causes the segment to be “ON” or visible. This AC drive configuration results in negligible DC voltage across each LCD segment. This insures long LCD display life. The polarity segment driver is “ON” for negative analog inputs. If V IN+ and V IN-are reversed, this indicator will reverse. When the TEST pin on the TC7106A is pulled to V+, all segments are turned “ON.” The display reads -1888. During this mode, the LCD segments have a constant DC voltage impressed. DO NOT LEAVE THE DIS-PLAY IN THIS MODE FOR MORE THAN SEVERAL MINUTES! LCD displays may be destroyed if operated with DC levels for extended periods.The display font and the segment drive assignment are shown in Figure5-1.FIGURE 5-1:Display Font and Segment AssignmentIn the TC7106A, an internal digital ground is generated from a 6-volt zener diode and a large P channel source follower. This supply is made stiff to absorb the large capacitive currents when the backplane voltage is switched.T SI =4F OSCx 1000Where: F OSC = external clock frequency.1000 =V INV REF© 2006 Microchip Technology Inc.DS21455C-page 9TC7106/A/TC7107/AFIGURE 5-2:TC7106A Block DiagramDS21455C-page 10© 2006 Microchip Technology Inc.6.0DIGITAL SECTION (TC7107A) Figure6-2 shows a TC7107A block diagram. It is designed to drive common anode LEDs. It is identical to the TC7106A, except that the regulated supply and backplane drive have been eliminated and the segment drive is typically 8mA. The 1000’s output (Pin 19) sinks current from two LED segments, and has a 16mA drive capability.In both devices, the polarity indication is “ON” for negative analog inputs. If V IN- and V IN+ are reversed, this indication can be reversed also, if desired.The display font is the same as the TC7106A.6.1System TimingThe oscillator frequency is divided by 4 prior to clocking the internal decade counters. The four-phase measurement cycle takes a total of 4000 counts, or 16,000 clock pulses. The 4000-count cycle is indepen-dent of input signal magnitude.Each phase of the measurement cycle has the follow-ing length:1.Auto-zero phase: 1000 to 3000 counts (4000 to12000 clock pulses).For signals less than full scale, the auto-zero phase is assigned the unused reference integrate time period: 2.Signal integrate: 1000 counts (4000 clockpulses).This time period is fixed. The integration period is: EQUATION 6-1:3.Reference Integrate: 0 to 2000 counts (0 to 8000clock pulses).The TC7106A/7107A are drop-in replacements for the 7106/7107 parts. External component value changes are not required to benefit from the low drift internal reference.6.2Clock CircuitThree clocking methods may be used (see Figure6-1):1.An external oscillator connected to Pin 40.2. A crystal between Pins 39 and 40.3.An RC oscillator using all three pins.FIGURE 6-1:Clock CircuitsT SI = 40001F OSC ⎛⎝⎞⎠Where: F OSC is the externally set clock frequency.FIGURE 6-2:TC7107A Block Diagram7.0COMPONENT VALUESELECTION7.1Auto-Zero Capacitor (C AZ)The C AZ capacitor size has some influence on system noise. A 0.47μF capacitor is recommended for 200mV full scale applications where 1LSB is 100μV. A 0.047μF capacitor is adequate for 2.0V full scale applications. A mylar type dielectric capacitor is adequate.7.2Reference Voltage Capacitor(C REF)The reference voltage used to ramp the integrator out-put voltage back to zero during the reference integrate cycle is stored on C REF. A 0.1μF capacitor is acceptable when V IN- is tied to analog common. If a large Common mode voltage exists (V REF- – analog common) and the application requires 200mV full scale, increase C REF to1.0μF. Rollover error will be held to less than 1/2 count.A mylar dielectric capacitor is adequate.7.3Integrating Capacitor (C INT)C INT should be selected to maximize the integrator out-put voltage swing without causing output saturation. Due to the TC7106A/7107A superior temperature coefficient specification, analog common will normally supply the differential voltage reference. For this case, a ±2V full scale integrator output swing is satisfactory. For 3 readings/second (F OSC = 48kHz), a 0.22μF value is suggested. If a different oscillator frequency is used, C INT must be changed in inverse proportion to maintain the nominal ±2V integrator swing.An exact expression for C INT is:EQUATION 7-1:C INT must have low dielectric absorption to minimize rollover error. A polypropylene capacitor is recommended.7.4Integrating Resistor(R INT)The input buffer amplifier and integrator are designed with class A output stages. The output stage idling current is 100μA. The integrator and buffer can supply 20μA drive currents with negligible linearity errors. R INT is chosen to remain in the output stage linear drive region, but not so large that printed circuit board leakage currents induce errors. For a 200mV full scale, R INT is 47kΩ. 2.0V full scale requires 470kΩ.Note:F OSC = 48kHz (3 readings per sec).7.5Oscillator ComponentsR OSC (Pin 40 to Pin 39) should be 100kΩ. C OSC is selected using the equation:EQUATION 7-2:For F OSC of 48kHz, C OSC is 100pF nominally.Note that F OSC is divided by four to generate the TC7106A internal control clock. The backplane drive signal is derived by dividing F OSC by 800.To achieve maximum rejection of 60Hz noise pickup, the signal integrate period should be a multiple of 60Hz. Oscillator frequencies of 240kHz, 120kHz, 80kHz, 60kHz, 48kHz, 40kHz, etc. should be selected. For 50Hz rejection, oscillator frequencies of 200kHz, 100kHz, 66-2/3kHz, 50kHz, 40kHz, etc. would be suitable. Note that 40kHz (2.5 readings/second) will reject both 50Hz and 60Hz.7.6Reference Voltage SelectionA full scale reading (2000 counts) requires the input signal be twice the reference voltage.*V FS = 2V REF.C INT =(4000)V INT1F OSCV FSR INT⎛⎝⎞⎠⎛⎝⎞⎠Where:F OSC=Clock Frequency at Pin 38V FS=Full Scale Input VoltageR INT=Integrating ResistorV INT=Desired Full Scale Integrator Output Swing ComponentValueNominal Full Scale Voltage200.0mV 2.000VC AZ0.47μF0.047μFR INT47kΩ470kΩC INT0.22μF0.22μFRequired Full Scale Voltage*V REF200.0mV100.0mV2.000V 1.000VF OSC =0.45RCIn some applications, a scale factor other than unity may exist between a transducer output voltage and the required digital reading. Assume, for example, a pres-sure transducer output is 400mV for 2000 lb/in2. Rather than dividing the input voltage by two, the reference voltage should be set to 200mV. This permits the trans-ducer input to be used directly.The differential reference can also be used when a digital zero reading is required when V IN is not equal to zero. This is common in temperature measuring instru-mentation. A compensating offset voltage can be applied between analog common and V IN-. The trans-ducer output is connected between V IN+ and analogcommon.The internal voltage reference potential available at analog common will normally be used to supply the converter’s reference. This potential is stable when-ever the supply potential is greater than approximately 7V. In applications where an externally generated reference voltage is desired, refer to Figure7-1.FIGURE 7-1:External Reference8.0DEVICE PIN FUNCTIONALDESCRIPTION8.1Differential Signal InputsV IN+ (Pin 31), V IN- (Pin 30)The TC7106A/7017A is designed with true differential inputs and accepts input signals within the input stage common mode voltage range (V CM). The typical range is V+ – 1.0 to V+ + 1V. Common mode voltages are removed from the system when the TC7106A/ TC7107A operates from a battery or floating power source (isolated from measured system) and V IN- is connected to analog common (V COM) (see Figure8-2). In systems where Common mode voltages exist, the 86dB Common mode rejection ratio minimizes error. Common mode voltages do, however, affect the inte-grator output level. Integrator output saturation must be prevented. A worst-case condition exists if a large positive V CM exists in conjunction with a full scale negative differential signal. The negative signal drives the integrator output positive along with V CM (see Figure). For such applications the integrator output swing can be reduced below the recommended 2.0V full scale swing. The integrator output will swing within 0.3V of V+ or V-without increasing linearity errors.FIGURE 8-1:Common Mode VoltageReduces Available Integrator Swing (VCOM ≠ VIN)8.2Differential ReferenceV REF+ (Pin 36), V REF- (Pin 35)The reference voltage can be generated anywherewithin the V+ to V-power supply range.To prevent rollover type errors being induced by largeCommon mode voltages, C REF should be largecompared to stray node capacitance.The TC7106A/TC7107A circuits have a significantlylower analog common temperature coefficient. Thisgives a very stable voltage suitable for use as areference. The temperature coefficient of analogcommon is 20ppm/°C typically.8.3Analog Common (Pin 32)The analog common pin is set at a voltage potentialapproximately 3.0V below V+. The potential is between2.7V and3.35V below V+. Analog common is tied inter-nally to the N channel FET capable of sinking 20mA.This FET will hold the common line at 3.0V should anexternal load attempt to pull the common line towardV+. Analog common source current is limited to 10μA.Analog common is, therefore, easily pulled to a morenegative voltage (i.e., below V+ – 3.0V).The TC7106A connects the internal V IN+ and V IN-inputs to analog common during the auto-zero cycle.During the reference integrate phase, V IN- is con-nected to analog common. If V IN- is not externally con-nected to analog common, a Common mode voltageexists. This is rejected by the converter’s 86dB Com-mon mode rejection ratio. In battery operation, analogcommon and V IN- are usually connected, removingCommon mode voltage concerns. In systems where V-is connected to the power supply ground, or to a givenvoltage, analog common should be connected to V IN-. [INThe analog common pin serves to set the analog section reference or common point. The TC7106A is specifically designed to operate from a battery, or in any measure-ment system where input signals are not referenced (float), with respect to the TC7106A power source. The analog common potential of V+ – 3.0V gives a 6V end of battery life voltage. The common potential has a 0.001% voltage coefficient and a 15Ω output impedance.With sufficiently high total supply voltage (V+ – V- > 7.0V), analog common is a very stable potential with excellent temperature stability, typically 20ppm/°C. This potential can be used to generate the reference voltage. An external voltage reference will be unneces-sary in most cases because of the 50ppm/°C maximum temperature coefficient. See Internal Voltage Reference discussion.8.4TEST (Pin 37)The TEST pin potential is 5V less than V+. TEST may be used as the negative power supply connection for external CMOS logic. The TEST pin is tied to the inter-nally generated negative logic supply (Internal Logic Ground) through a 500Ω resistor in the TC7106A. The TEST pin load should be no more than 1mA.If TEST is pulled to V+ all segments plus the minus sign will be activated. Do not operate in this mode for more than several minutes with the TC7106A. With TEST=V+, the LCD segments are impressed with a DC voltage which will destroy the LCD.The TEST pin will sink about 10mA when pulled to V+.8.5Internal Voltage ReferenceThe analog common voltage temperature stability has been significantly improved (Figure8-3). The “A”version of the industry standard circuits allow users to upgrade old systems and design new systems without external voltage references. External R and C values do not need to be changed. Figure8-4 shows analog common supplying the necessary voltage reference for the TC7106A/TC7107A.FIGURE 8-3:Analog Common Temperature CoefficientFIGURE 8-4:Internal Voltage ReferenceConnection。
1.描述数字化与模拟化的优缺点？(重点数字化)
1.描述数字化与模拟化的优缺点？（重点数字化）数字信号表示的是0，1代码；模拟信号是波型表示的。
数字信号是不连续的模拟信号是连续的模拟信号指幅度的取值是连续的（幅值可由无限个数值表示）。
时间上连续的模拟信号连续变化的图像（电视、传真）信号等，时间上离散的模拟信号是一种抽样信号，数字信号指幅度的取值是离散的，幅值表示被限制在有限个数值之内。
二进制码就是一种数字信号。
二进制码受噪声的影响小，易于有数字电路进行处理，所以得到了广泛的应用。
1．模拟通信模拟通信的优点是直观且容易实现，但存在两个主要缺点。
（1）保密性差模拟通信，尤其是微波通信和有线明线通信，很容易被窃听。
只要收到模拟信号，就容易得到通信内容。
（2）抗干扰能力弱电信号在沿线路的传输过程中会受到外界的和通信系统内部的各种噪声干扰，噪声和信号混合后难以分开，从而使得通信质量下降。
线路越长，噪声的积累也就越多2.理发师悖论（了解一下）内容一个城市里唯一的理髮师只给所有不给自己理髮的人理髮。
这个城市不可能存在，因为：如果理髮师不给自己理髮，他需要遵守规则，给自己理髮如果理髮师给自己理髮，如遵守规则，他不准给自己理髮换用集合语言：可以把集合分为两类，凡不以自身为元素的集合称为第一类集合；凡以自身作为元素的集合称为第二类集合。
显然每个集合或为第一类集合或为第二类集合。
设为第一类集合的全体组成的集合。
如果是第一类集合，由集合的定义知:应该是的元素，这表明是第二类集合如果是第二类集合，那么是它自身的元素二者皆导出矛盾，而整个讨论逻辑上是没有问题的。
问题只能出现在集合的定义上。
补救由於罗素悖论的出现所引发的第三次数学危机，公理化集合论势在必行。
德国数理逻辑学家策梅洛（Zermelo，1871年-1953年）应用自己的公理系统，使得集合在公理的限制下不会太大，从而避免了罗素悖论。
经过改进，这一系统形成了现在被称为ZF系统的公理集合论体系。
这个体系至今没有发现悖论。
DT830B_数字万用表装配说明
实验原理1、ICL7106原理介绍ICL7106是目前广泛应用的一种3½位A/D转换器，能构成3½位液晶显示的数字电压表。
一、ICL7106的工作原理1. ICL7106的性能特点（1）采用＋7V～＋15V单电源供电，可选9V叠层电池，有助于实现仪表的小型化。
低功耗（约16mW），一节9V叠层电池能连续工作200小时或间断使用半年左右。
（2）输入阻抗高（1010Ω）。
内设时钟电路、＋2.8V基准电压源、异或门输出电路，能直接驱动3½位LCD显示器。
（3）属于双积分式A/D转换器，A/D转换准确度达±0.05％，转换速率通常选2次／秒～5次／秒。
具有自动调零、自动判定极性等功能。
通过对芯片的功能检查，可迅速判定其质量好坏。
（4）外围电路简单，仅需配5只电阻、5只电容和LCD显示器，即可构成一块DVM。
其抗干扰能力强，可靠性高。
（5）工作温度范围是0～＋70℃，但受LCD限制，仪表环境温度一般为0～＋40℃，相对湿度不超过80％。
2. ICL7106的引脚功能ICL7106采用DIP－40封装，引脚排列如上图所示。
U+、U－分别接9V电源（E）的正、负极。
COM为模拟信号的公共端，简称模拟地，使用时应与IN－、UREF－端短接。
TEST是测试端，该端经内部500Ω电阻接数字电路的公共端（GND），因二者呈等电位，故亦称做数字地。
该端有两个功能：①作测试指示，将它接U＋时LCD显示全部笔段1888、可检查显示器有无笔段残缺现象；②作为数字地供外部驱动器使用，来构成小数点及标志符的显示电路。
a1～g1、a2～g2、a 3～g3、bc4分别为个位、十位、百位、千位的笔段驱动端，接至LCD的相应笔段电极。
千位b、c段在LCD内部连通。
当计数值N＞1999时显示器溢出，仅千位显示“1”，其余位消隐，以此表示仪表超量程（过载溢出）。
POL为负极性指示的驱动端。
BP为LCD背面公共电极的驱动端，简称“背电极”。
IC7106各引脚功能教学难点
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IC7106引脚介绍
A1—G1、 A2—G2、 A3——G3 分别为个位、十位、百位的笔 段驱动端，依次接至个位、十 位、百位液晶显示屏的相应笔 段电极。 POL:负极性指示的驱动端 BP:液晶显示屏背面公共电极 的驱动端，简称“背电极” OSCl—OSC3:时钟振荡器的引 出端。 VREF+ 基准电压正端， VREF- 基准理
1.7106内部模拟电路 模拟电路为双积分式A/D转换器，主要是实现将输 入的模拟信号转换成数字信号输出。
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IC7106基本工作原理
2.7106内部数字电路 数字电路主要由时钟振 荡器、分频器、计数器、锁 存器、译码器、异或门相位 驱动器、控制逻辑、三位半 LED显示器 组成。主要实现 的功能是将数字信号译码输 出。
CREF+、CREF－:外接基准电 容端。 INLO( IN- )、INHI ( IN+ )为模拟输入信号低端和高 端， TEST测试端 ，4V+、V-为电 源正负极， COM 模拟信号的公共端，模 拟地， INTEN 积分器输出端， BUF为缓冲器。
6
认识IC7106
认识IC7106
安徽桐城望溪职校 江文飞
教学目的及要求
教学目的： 了解IC7106基本工作原理，掌握IC7106各引脚功能。 教学重点： IC7106各引脚功能。 教学难点： IC7106基本工作原理。
IC7106简介
采用＋7V～＋15V单电源供电，可选9V叠 层电池， 输入阻抗高（1010Ω ） 属于双积分式A/D转换器 外围电路简单，仅需配5只电阻、5只电 容和LCD显示器，即可构成一块DVM； 工作温度范围是0～＋70℃
icl7106 原理
ICL7106是一款由Maxim公司生产的单片模拟-数字转换器（ADC），具有高输入阻抗，无需外部显示驱动电路。
它内部集成了极性变换、段解码器、基准电压、时钟电路和LCD驱动器等组件。
ICL7106的工作原理如下：
1. 输入信号：ICL7106的输入信号为模拟电压，通过差动输入端IN和模拟地COM相连。
2. 基准电压：ICL7106内部集成了基准电压发生器，在V到COM之间产生2.8V基准电压。
外部可通过分压电阻调整基准电压的值。
3. 积分转换：ICL7106采用双积分型ADC，将输入的模拟电压信号转换为数字信号。
它包括积分器和求和放大器，通过积分和求和过程，将模拟信号转换为数字信号。
4. 输出编码：转换后的数字信号经过七段译码器，输出为BCD码，可直接驱动液晶显示器（LCD）。
5. 控制电路：ICL7106内部集成了时钟振荡电路、自动极性变换和调零电路等，实现对ADC的控制。
关于ICL7606及ICL7607的介绍
4、反向积分阶段
最后一个阶段是反向积分阶段。低端输入在芯片 内部链接街道模拟公共端，高端输入通过先前已 充电的电容进行连接，内部电路是电容极性正确 的连接以确保积分器的输出能回到零。积分器的 输出回到零的时间正比于输入信号的大小。对应 的数字输出为：显示值=
五、差动输入
输入端能承受输入放大器允许的共模电压范围内 的差动电压。即在比正电源0.5V和比负电源高1V 的范围。在此范围内，电路有86dB的共模抑制比。 然而必须注意的是积分器的输入不能进入饱和区， 一种最坏的情况可能是在输入端有一接近满量程 的负向差动电压，同时又有一个较大的共模正向 电压，负向的差动电压使得积分器的输出向正方 向走，而此时积分器输出的正向摆幅又被正向共 模电压所挤占，在这种严格的应用条件下，可适 当地牺牲一些精度，将积分器的输出电压摆幅降 低到低于所推荐的2V满量程。积分器的输出可在 比正电源低0.3V或比负电源高0.3V的范围内摆动 而不影响线性度。
2、自动校零阶段
在自动校零阶段做三件事情。第一，内部高端输 入和低端输入与外部管脚脱开，在内部与模拟公 共管脚短接。第二，参考电容充电到参考电压值。 第三，围绕整个系统形成一个回路，对自动校零 电容Caz,以补偿缓冲放大器、积分器、和比较器 的失调电压。由于比较器包含在回路中，因此自 动校零的精度仅受限于系统噪声。任何情况下， 折合到输入端的失调电压小于10uv。
这为前面所涉及的 TEST-37管脚直接接 高电平的结果显示
这是我们测的 第一组数据， 即与即与标准电压表 进行对比 的记录显示
实验总结如下： 一）注意正确的正负电源的接法。 二）基准电压（36，35）的设定， COMMON(32)的大小（1K的调整)。 三）小数点问题。 四）量程问题（改变1M电阻） 五）ICL7106与ICL7107区别。 六）数字显示
数字表7106芯片检修几例
数字表7106芯片检修几例基本信息主题类别：知识_经验仪表品牌：其它品牌仪表型号：无体积分类：其它样式显示字数：三位半是否拆机：没有拆机数字表显示溢出检修一例一只芯片为7106的数字表，开机时液晶显示屏左侧显示溢出符号“1”，一般来说出现这种现象时，芯片损坏的可能性较大。
经测试发现芯片的①脚对地为2．8V，基准电压(即36脚对35脚)为100mV，完全正常，看来芯片并没有损坏。
分析能够引起过载溢出的原因只能是芯片的输入端VIN的电压高于基准电压100mV。
实际测量31脚对地的电压小于100mV时，发现故障表上的溢出符号“-1”消失，而显示出一定的数字。
经仔细分析判断是c1的一只引脚焊点不良(见图中“故障点”所指处)，造成芯片的31脚实际上同外围元件完全断开，其上的感应电压超过了100mV而引起的过载。
实际测量31脚对地电压时，由于外围元件的钳位作用恰好使电压值小于100mV。
处理好故障点后，31脚对地电压为0V，显示屏显示“000”，故障排除。
数字万用表显示“1888”故障数字表故障为“各挡均显示1888”；这是一种三位半数字万用表，该仪表主要芯片是ICL7106。
由于是因“用错量程，损坏仪表”且显示为“1888”大多为ICL7106第①脚与第37短路损坏，换同型号芯片即可。
判断方法如下：打开仪表，从线路板上断开IC7106第①脚和第26脚，把电池接入第①脚(正)、第26脚(负)，用一台正常数字表黑表笔接“COM”，红笔分别测量这两脚电压，正常时，①脚+2．8v(不得超过+3．2v)，26脚-5．8v(随电池电压高低而不同。
如果以上电压正常，再测Ic7106第37脚(电压应为负值)，如接近①脚电压说明第37脚外围元件与①脚短路，重点检测第37脚外围元件，但这种情况较少见。
2．如果①脚、26脚电压不正常，且第37脚仍有正电压，则说明Ic7106，内部第①脚与第37脚短路，必须更换同型号ICL7106。
ICL71077106中文资料
ICL7106/ICL7107 三位半LCD/LED显示&A/D转换器ICL7106和ICL7107是高性能、低功耗的3位半A/D转换器，包含七段译码器、显示驱动器、参考源和时钟系统。
ICL7106含有一背电极驱动线，适用于液晶显示（LCD）；ICL7107可直接驱动发光二极管（LED）管脚排列主要特点●保证零电平输入时，各量程的读值均为零●1pA典型输入电流●真正的差动输入和差动参考源，直接LCD显示驱动（IC7106）和LED显示驱动（IC7107）●低噪声（小于15μV p-p）●芯片集成基准时钟●低功耗--典型值小于10mW●无需外接有源电路极限参数（最大额定值）除非特别说明，T amb=25℃注1：输入电压允许超过电源电压，但输入电流必须限制在±100μA 注2：电路安装在实验板上，在自由流通空气中测试ΦJA电气参数（除非特别说明，ICL7106和ICL7107均在环境温度T amb=25℃，时钟频率F clock=48Khz条件下测试。
ICL7107的测试图见图2，所有元件管脚均焊接在PCB上）注3：设计保证，不作批生产测试注4：背电极驱动信号相位与不显示的字符段一致，与要显示的字符段成180°的相位，频率为20倍的转换频率，平均直流电压小于50mV应用参数选用参考ICL7107显示：LED 类型：未编码的共阳LED数码管功能说明1.模拟部分图3表示ICL7106和ICL7107的模拟部分。
每个测量周期分为三个阶段，它们分别是1）自动校零阶段（A～Z）2）信号积分阶段（INT）3）反向积分阶段（DE）2.自动校零阶段在自动校零阶段做三件事。
①内部高端输入和低端输入与外部管脚脱开，在内部与模拟公共管脚短接。
②参考电容充电到参考电压值。
③围绕整个系统形成一个闭合回路，对自动校零电容C AZ充电，补偿缓冲放大器、积分器和比较器的失调电压。
由于比较器包含在回路中，因此自动校零的精度仅受限于系统噪声。
7107芯片简介
ICL7107/IC7106是一块应用非常广泛的集成电路。
它包含3 1/2位数字A/D转换器，可直接驱动LED数码管，内部设有参考电压、独立模拟开关、逻辑控制、显示驱动、自动调零功能等。
本文主要介绍其管脚及主要参数,后续文章将介绍ICL7107的应用及注意事项.ICL7107管脚图ICL7107管脚图ICL7107中文资料3 1/2位双积分型A/D转换器ICL7107的基本特点ICL7107是31/2位双积分型A/D转换器，属于CMoS大规模集成电路，它的最大显示值为士1999，最小分辨率为100uV，转换精度为0.05士1 个字。
能直接驱动共阳极LED数码管，不需要另加驱动器件，使整机线路简化，采用士5V两组电源供电，并将第21脚的GND接第30脚的IN 。
在芯片内部从V+与COM之间有一个稳定性很高的2.8V基准电源，通过电阻分压器可获得所需的基准电压VREF 。
能通过内部的模拟开关实现自动调零和自动极性显示功能。
输入阻抗高，对输入信号无衰减作用。
整机组装方便，无需外加有源器件，配上电阻、电容和LED共阳极数码管，就能构成一只直流数字电压表头。
噪音低，温漂小，具有良好的可靠性，寿命长。
芯片本身功耗小于15mw（不包括LED）。
不设有一专门的小数点驱动信号。
使用时可将LED共阳极数数码管公共阳极接V+.可以方便的进行功能检查。
ICL7107的引脚图ICL7107的引脚图及典型电路。
ICL7107引脚功能V+和V-分别为电源的正极和负极，au-gu,aT-gT,aH-gH：分别为个位、十位、百位笔画的驱动信号，依次接个位、十位、百位LED 显示器的相应笔画电极。
Bck：千位笔画驱动信号。
接千位LEO显示器的相应的笔画电极。
PM：液晶显示器背面公共电极的驱动端，简称背电极。
Oscl-OSc3 ：时钟振荡器的引出端，外接阻容或石英晶体组成的振荡器。
第38脚至第40脚电容量的选择是根据下列公式来决定：Fosl = 0.45/RCCOM ：模拟信号公共端，简称“模拟地”，使用时一般与输入信号的负端以及基准电压的负极相连。
7106万用表芯片原理
7106万用表芯片是一款由Intersil制造的35位模数转换器，具有高精度、低功耗、内部基准电压源、LCD驱动器、过量程和欠量程检测、自动极性和低噪声等特点。
它广泛应用于电子行业的多功能高精度模数转换器，是确保各种应用中准确、高效的数据采集和测量的重要工具。
本文将为您详细介绍7106万用表芯片的工作原理，以及如何判断它的好坏。
7106万用表芯片的工作原理主要包括以下几个方面：1.模拟输入：7106万用表芯片通过其模拟输入引脚接受模拟输入信号，模拟输入信号可以是电压、电流或电阻等。
这些信号被转换成对应的数字信号，并通过ICL7106的A/D转换器进行转换。
2.A/D转换器：ICL7106内部集成了35位的A/D转换器，该转换器能够将模拟信号转换为数字信号，并通过数据总线传输到处理器。
A/D转换器的转换精度非常高，可以精确测量、节约能源、简化设计和满足不同电子需求。
3.处理器：ICL7106内部集成了一个低功耗的处理器，处理器主要负责处理来自A/D转换器的数据，并将其存储在存储器中。
处理器还可以执行各种计算和逻辑操作，例如进行数字信号的滤波、计算、比较等。
4.存储器：ICL7106内部集成了一个存储器，用于存储来自A/D 转换器的数据和处理器计算的结果。
存储器的容量可以根据需要进行扩展，以满足不同的数据存储需求。
5.数字输出：ICL7106通过其数字输出引脚向外输出数字信号，数字信号可以是电压、电流或电阻等。
数字输出信号可以通过数据总线传输到其他设备，例如数字万用表、面板仪表、温度测量、过程控制和电池供电设备等。
如何判断7106万用表芯片的好坏？判断万用表芯片ic7106的好坏判断的关键是看电源正极到com和电源负极到com的电压，如果这两个电压不对，可以确定芯片已经损坏。
另外，还可以通过测量芯片的输入和输出引脚的电压和电流，以及处理器的运行状态等方面来判断芯片的好坏。
如果芯片出现故障，可能会导致万用表无法正常工作，因此需要及时进行维修或更换。
ICL7106CPL中文资料
0 to 70
40 Ld PDIP(Pb-free) (Note 3)
E40.6
ICL7107RCPL
ICL7107RCPL
0 to 70
40 Ld PDIP (Note 1)
E40.6
ICL7107RCPLZ (Note 2)
ICL7107RCPLZ
0 to 70
40 Ld PDIP (Pb-free) (Notes 1, 3) E40.6
元器件交易网
®
Data Sheet
ICL7106, ICL7107, ICL7107S
December 1, 2005
FN3082.8
31/2 Digit, LCD/LED Display, A/D Converters
The Intersil ICL7106 and ICL7107 are high performance, low power, 31/2 digit A/D converters. Included are seven segment decoders, display drivers, a reference, and a clock. The ICL7106 is designed to interface with a liquid crystal display (LCD) and includes a multiplexed backplane drive; the ICL7107 will directly drive an instrument size light emitting diode (LED) display.
ICL7106CM44ZT (Note 2)
ICL7106CM44Z
7106中文资料
版本：1.0 2001-04-25 第 1 页 共 4 页概述CS7106AGP 是一种具有直接驱动LCD 功能的3位半A/D 转换电路。
电路具有很强的抗干扰能力。
CS7106AGP 的用途十分广泛，它可以组装成各种体积小、重量轻、便于携带的数字仪表，也可用于数控系统。
CS7106AGP 可与国外同类型号的电路互换使用。
功能特点! 采用单电源供电，电压范围7～15V ，可使用9V 叠层电池。
! 温度漂移低。
! 输出形式为异或门输出，能直接驱动LCD 。
! 采用CMOS 差动输入，输入阻抗高，对输入信号无衰减作用。
! 内部噪声低，显示稳定。
! 能通过内部模拟开关实现自动调零和自动极性显示。
! 内部有时钟电路，可接阻容元件构成多谐振荡器。
! 在芯片内部V +与COM 端之间，有一个稳定性很高的3.0V （典型值）基准电压源。
! 具有显示保持、电源低电压显示、A/D 正积分显示和A/D 反积分显示（注：DIP40封装无此四种功能）。
! 整机组装方便，所需外围元件少。
! 典型封装形式为DIP40（也可采用软封）。
管脚说明1. V +和V -分别接电源的正极和负极。
2. A1～G1、A2～G2、A3～G3分别为个位、十位、百位笔划的驱动信号，依次接LCD 的个位、十位、百位的相应笔划电极，LCD 显示器笔划见下图。
3. AB4：千位笔划驱动信号，接千位液晶显示器的b 、c 两个笔划电极。
当计数值大于1999时，发生溢出，千位数显示“1”，表示超量程显示。
4. POL ：负极性指示，接千位数码g 端，当BCL 端输出的方波与背电极方波的相位相反时，显示负号“-”。
5. BP ：LCD 背面公共电极的驱动端。
6. OSC1～OSC3：时钟振荡器的引出端，外接阻容元件组成多谐振荡器。
7. COM ：模拟信号公共端，简称“模拟地 ”。
8. TEST ：逻辑电路的公共地，简称“逻辑地”，可接负电源供外部驱动器使用，例如组成小数点显示电路。
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图1－3 数字电压表原理框图
计数器
第三章 万用表的电路原理及装配
＋ Vin －
+ VREF
－ VREF
CREF
RC滤波器
模拟开关
缓冲器
积分器与 比较器
模拟电路
逻辑控制器
Fcp 10KHz
RC振荡器 F0 40KHz 分频器Ⅰ TCP=0.1ms 分频器Ⅱ
LCD显示器 数字电路 相位驱动器 七段译码器
锁存器
图1－3 数字电压表原理框图
计数器
第三章 万用表的电路原理及装配
3.1万用表的基本结构：
3.1.3 数字电压表的电路原理框图 模拟电路与数字电路相辅相成，
互相制约，共同完成数字万用表所具 有的功能。模拟电路控制数字电路的 工作状态与显示结果。而数字电路控 制模拟电路中模拟开关的“接通”与 “断开”。
14 G1
一般规定为7～15V，常选用9V叠层电
E1 15
池，消耗电流仅为1.8mA，功耗仅为
16 D2
16mW。
C2 17
7106芯片有很高的输入阻抗，典
18 B2
V+
OSC2
OSC3 INTEN
00
7106
型值为1010Ω，对输入信号无衰减作用。 A2 19
并且，外围电路简单，可直接驱动 LCD
第三章 万用表的电路原理及装配
3.1万用表的基本结构：
3.1.3 数字电压表的电路原理框图
+ VREF
－ VREF
CREF
＋ Vin －
RC滤波器
模拟开关
缓冲器
积分器与 比较器
模拟电路
逻辑控制器
Fcp 10KHz
RC振荡器 F0 40KHz 分频器Ⅰ TCP=0.1ms 分频器Ⅱ
LCD显示器 数字电路 相位驱动器 七段译码器
R / I 转换
功
量
电
能
程
选 择
V~ / I 转换
选 择
流 表
V / I 转换 图1-1 模拟式万用表的结构
R / V 转换
功
量
能
程
基本量
选 择
V~ / V 转换
选 择
程数字 电压表
I / V 转换
图1-2袖珍式数字万用表的结构
第三章 万用表的电路原理及装配
3.1万用表的基本结构： 输入
3.1.1.模拟式万用表的结构
第三章 万用表的电路原理及装配
3.1万用表的基本结构 3.2双积分A/D转换器的工作原理 3.3万用表功能的扩展 3.4万用表的装配与调试
第三章 万用表的电路原理及装配
3.1万用表的基本结构
3.1.1 模拟式万用表的结构 3.1.2 数字万用表的结构 3.1.3 数字电压表的原理框图 3.1.4 液晶显示概述 3.1.5 大规模集成电路——7106芯片简介
模拟电路和数字电路都集成在一 块大规模集成电路——7106芯片上。
第三章 万用表的电路原理及装配
3.1万用表的基本结构：
3.1.4 液晶显示概述 数字万用表的液晶显示器是采用段电极显
示的方式来实现的，也就是液晶显示器的前部 电极被分割成a,b,c,d,e,f,g七段，各段电极 a,b,c,d,e,f,g与“7106”集成电路芯片中的 “BP”引脚，也叫背电极。背电极也是前部电 极的共用电极。若是各段前部电极与背电极之 间电位相等时，则液晶不显示。若某一段或几 段前部电极与背电极存在电位差时，则液晶显 示。这样就可以根据被测参数的实际情况分别 显示十进制中的1，2，3，4，5，6，7，8， 9，0这十个数。
第三章 万用表的电路原理及装配
3.1万用表的基本结构：
B1
D1
OSC1 HOLD TEST
DEEN
11 10 9 8 7 6 5 4 3 2 1
3.1.5 大规已模集成电路—7106芯
片简介
C1 12 A1
7106芯片是数字万用表的核心部 件，它已封装在每块印制电路板的上
F1 13
端。采用单电源供电，电压范围宽，
R / V 转换
功
量
能
程
基本量
选 择
V~ / V 转换
选 择
程数字 电压表
I / V 转换
图1-2袖珍式数字万用表的结构
第三数字电压表的电路原理框图 数字电压表由两部分电路构成：
即模拟电路部分和数字电路部分。在 模拟电路部分主要由滤波器、模拟开 关、缓冲器、积分器和比较器构成。 在数字电路部分主要由振荡器、分频 器、逻辑控制器、计数器、锁存器、 译码器、相位驱动器和液晶显示器构 成。
3.1.2.数字万用表的结构
在数字万用表结构中，其核心电
路是由A/D转换器及液晶显示电路等组
成的基本量程数字电压表。转换器的
功能是将被测信号转换成直流电压后
再进行测量。功能选择一般通过拨档
开关来实现，有的表可通过电路自动
切换来完成。
输入
R / I 转换
功
量
电
能
程
选 择
V~ / I 转换
选 择
流 表
V / I 转换 图1-1 模拟式万用表的结构
a
f
b
g
e
c
d
图1－4 七段LCD显示器字段
第三章 万用表的电路原理及装配
3.1万用表的基本结构：
3.1.5 大规模集成电路——7106芯片简介
B1
D1
OSC1 HOLD TEST
DEEN
11 10 9 8 7 6 5 4 3 2 1
C1 12 A1 F1 13 14 G1 E1 15
V+
OSC2
第三章 万用表的电路原理及装配
R / I 转换
功
量
电
3.1万用表的基本结构：
能 输入 选
择
程
V~ / I 转换
选 择
流 表
3.1.1.模拟式万用表的结构
3.1.2.数字万用表的结构
V / I 转换
图1-1 模拟式万用表的结构
R / V 转换
功
量
能
程
基本量
输入 选 择
V~ / V 转换
选 择
程数字 电压表
I / V 转换 图1-2袖珍式数字万用表的结构
第三章 万用表的电路原理及装配
3.1万用表的基本结构： 输入
3.1.1.模拟式万用表的结构 3.1.2.数字万用表的结构
在模拟式万用表结构中，核心 部件是磁电式电流表头，转换器的 功能是将被测参数——R、V、I统一 转换成直流电流后再进行测量。而 量程的选择是通过旋转多层开关来 输入 实现。
OSC3 INTEN
16 D2 C2 17
18 B2
7106
19 A2
20 F2
E2 21
22 D3
F3
AB4
BP
A3
G2
23 24 25 26 27 28 29 30 31 32 33
B3
E3
POL
G3
C3
LB
图2-1 44脚7106管脚排列
44 VREF+ 43 VREF42 CREF+ 41 CREF40 COM 39 INHI 38 INLO 37 A/Z 36 BUF 35 INT 34 V-