Write the disadvantage of single slope integrator adc. Write the disadvantage of single slope integrator adc and. Dual slope adc architecture a dual slope adc ds adc integrates an unknown input voltage vin for a fixed amount of time tint, then deintegrates tdeint using a known reference voltage vref for a variable amount of time see figure 2. Difference between adc typescounter,flash,sar,dual slope. It is pretty slow, but its ability to reject highfrequency noise and fixed low frequencies such as 50 hz or 60 hz makes it. So for a 2v full scale the lsb or the resolution is 1mv.
This page covers difference between various adc types including block diagram, equation etc. The dualslope adc architecture was truly a breakthrough in adcs for high resolution applications such as digital voltmeters dvms, etc. A block diagram of the circuit figure 1 includes a single primary li cell, a millivoltoutput bridge sensor, a differential amplifier, and the dualslope adc, plus correction circuitry for offset, zero, and span. The peak value attained contains the only clue but that is unknown to this type of adc. The tc500 is the base 16bit max device and requires both positive and negative power supplies. During the 2nd slope negative slope the input voltage is disconnected and the counter begins. In this thesis, a novel low power analogtodigital converter adc for the digitization and analyzation of the. Dual slope adcs are used in applications demanding high accuracy. Then a reference input is switched to the integrator, which integrates down from the level determined by the unknown until the starting level is reached. It is pretty slow, but its ability to reject highfrequency noise and fixed low frequencies such as. The singleslope adc suffers the disadvantage of calibration drift. If the output of the counter is a binary number, it will therefore be a binary representation of the input voltage.
This paper gives an overview of the development of columnparallel adcs that enable the highspeed, powerefficient readout of highresolution cmos imagers. Though the operation is quite slow, it has the ability to. The analog input signal is connected to the input terminal of a comparator that. Both adcs make use of simple opamp circuits and control logic to do most of their work. The is the basic idea behind the socalled singleslope, or integrating adc. There are many types of analogtodigital converters adcs which can be classified according to the concept on which they were designed. A dualslope adc, on the other hand, averages together all the spikes and dips within the integration period. Unlike a dualslope,this converter has no inherent noise rejection capability. I found a reference to the enhanced dualslope in the 2nd reference hp journal, 40 2.
Feb 24, 2014 a video by jim pytel for renewable energy technology students at columbia gorge community college. A video by jim pytel for renewable energy technology students at columbia gorge community college. Slope integrating adc slope integrating adc the single slope adc suffers all the disadvantages of the digital ramp adc, with the added drawback of calibration drift. A low power midrail dual slope analogtodigital converter for. Columnparallel singleslope adcs for cmos image sensors martijn snoeij, albert theuwissen, kofi makinwa and johan huijsing. Integrating dual slope ad converter the ald500 series is alds newest family of monolithic cmos analog processor chips that implement precision, low power, low noise integrating dual slope ad converters having a resolution of 16, 17 and 18 bits, plus sign bit and overrange bit. This analogtodigital converter adc has been at the heart of the digital volt meter. Single slope analog todigital ad conversion by stephen ledford csic product engineering austin, texas introduction the most common implementation for analog todigital ad conversion among motorola microcontrollers is the successive approximation sar method. We use quasisynchronous sampling with the rst harmonic of the voltage network. The accurate correspondence of this adcs output with its input is dependent on the voltage slope of the integrator. This article illustrates four techniques applied to the wellknown dual slope analog todigital converter adc in.
Scottr9 grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. Figure 2 shows a simple block diagram of this type of adcs11. The dual slope adc dsadc is a type of analogtodigital conversion with low input bandwidths. Single slope adc architecture dual slope adc course hero. Adc converter technologies may occasionally convert a spike or dip because it captures the signal repeatedly at a single point in time. Request pdf dual slope adc using noninverting controlled bootstrap circuit this article presents the simple and inexpensive method to realize the dualslope analogtodigital converter adc. Hank zumbahlen, with the engineering staff of analog devices, in linear circuit design handbook, 2008. Adc dac converter free download as powerpoint presentation. The output is also extremely simple, just a pulse that needs to be timed which can be done with even the simplest micro controllers. As a minimum, each device contains the integrator, zero crossing comparator and proc essor interface logic. Columnparallel dualslope integrating adc pdf version. Analog to digital converter how adc works with pic mcu. This note explains the use of offset flipping for onthefly calibration of the adc.
The dualslope adc dsadc is a type of analogtodigital conversion with low input bandwidths. Adc dac converter analog to digital converter digital. In some countries this may not be legally possible. I have a project on doing simple dual slope adc using only our lab kit component. Whats the difference between sar and deltasigma adcs.
Sep 26, 2019 introduction, basic dac techniques, weighted resistor dac, r2r ladder dac, inverted r2r dac, and ic 1408 dac, different types of adcs parallel comparator type adc, counter type adc, successive approximation adc and dual slope adc. This paper presents an interesting method using a dualslope analoguetodigital converter dsadc with high resolution to measure the rms value of the current, voltage, active power, and energy for linear and nonlinear loads. Although singleslopeintegratorswere used in early ads and voltmeters their dependence on an integrating capacitor for stability was considered an intolerable weakness. Dual slope adc using noninverting controlled bootstrap. A complete device list and corresponding data sheets or these products can be found at. In its basic implementation, the dual slope converter, the unknown input voltage is applied to the input of the integrator and allowed to ramp for a fixed time period the runup period. Dualslope adc architecture a dualslope adc dsadc integrates an unknown input voltage v in for a fixed amount of time t int, then deintegrates t deint using a known reference voltage v ref for a variable amount of time. Precise calibration of dualslope adcs application note maxim.
Singleslope analogtodigital ad conversion by stephen ledford csic product engineering austin, texas introduction the most common implementation for analogtodigital ad conversion among motorola microcontrollers is the successive approximation sar method. Precision analog front ends with dual slope adc microchip. During the first slope positive slope the sampling time is a fixed value and therefore the duration gives no clue about what the input voltage is. Today, almost every electronic product contains an analogtodigital converter. A fascinating question has always been how can you convert an analog voltage to an equivalent digital word. A single adc cell no control or bias circuitry objectives. It covers counter type adc,parallel comparator flash adc, sarsuccessive approximation register type adc,sigma delta adc, dual slope integrating type adc etc. A dualslope adc dsadc integrates an unknown input voltage v. A dualslope integration based analogtodigital convertor.
An integrating adc in which the unknown signal is converted to a proportional time interval, which is then measured digitally. We now consider the singleslope and the dualslope adcs. Mar 22, 2014 the single slope analogtodigital converter ss adc is the most commonly used columnlevel adc for highspeed industrial, complementary metaloxide semiconductor cmosbased xray image sensors because of its small chip area the width of a pixel, its simple circuit structure, and its low power consumption. The dual slope adc is an analogtodigital converter that does its conversion using quite low bandwidth as its input. Write the disadvantage of single slope integrator adc and how does dual slope integrator adc overcome this problem. A dualslope integration based analog todigital convertor hasan krad department of computer science and engineering, college of engineering, qatar university, p.
A dualslope adc dsadc integrates an unknown input voltage v in for a fixed amount of time t int, then deintegrates t deint using a known reference voltage v ref for a variable amount of time see. A dualslope adc, on the other hand, averages together all the spikes and dips within the integration period, thus providing an output with greater noise immunity. Dual slope adc design from power, speed and area perspectives conference paper pdf available april 2009 with 2,318 reads how we measure reads. Now the input is integrated for 300ms and the integrated. Ccjrootv8n5pdf group 4 general pathology, logic and cytologic techniques free download as pdf file. Integrated circuits applications notes pdf ica notes pdf download ica 5. Therefore, the columnparallel single slope architecture fig. Single slope analogtodigital ad conversion by stephen ledford csic product engineering austin, texas introduction the most common implementation for analogtodigital ad conversion among motorola microcontrollers is the successive approximation sar method. The advent of the dualslope converter see about integrating converters and capacitors solved the problem of integrating capacitor. The ex input signal is directly coupled to the comparator input with no filtering. The dual slope integration type of ad conversion is a very popular method for digital voltmeter applications.
When compared to other types of adc techniques, the dual slope method is slow but is quite adequate for a digital voltmeter used for laboratory measurements. This work has been released into the public domain by its author, scottr9 at english wikipedia. This paper presents the design of an adjustable 14bit dual slope adc with wide input range for low frequency applications. Dual slope converter an integrating adc in which the unknown. With the advent of the advanced technology and the need for more. To overcome this sensitivity to the component values, the dualslope integrating architecture is used. The dualslope conversion improvement radojle radetic1, marijana pavlovkagadejev2, nikola milivojevic3 abstract. We explain why the slightly more complicated dualslope adc is generally a better choice of adc than the singleslope converter. Successive approximation register type adc, sigma delta adc,dual slope integrating type adc etc.
Analogtodigital converters adcs translate analog signals into digital values for use in processing and control systems. Dual slope or integrating type adc watch more videos at lecture by. An alternative ad conversion technique uses the single slope ad converter. The conclusion of the study showed the efficiency of the dual slope adc as compared to other adcs, most especially the single slope adc keywords dual slope, adc, 8 bit, counter, cascaded 4 bit. The higher the input voltage, the greater the magnitude of the voltage stored on the integrator during this phase. As shown in figures 410a and 410b, the voltage to be measured v x is input to an integrator, charging the capacitor for a fixed time interval t 1, which corresponds to a certain number of clock cycles.
As we know adc is the short form of a to d converter. The single slope adc suffers all the disadvantages. Pdf the dualslope adc dsadc is a type of analogtodigital conversion with low input bandwidths. The charge on the capacitor at time t1 is proportional to the average value of vx times t1. Pdf the dualslope conversion improvement researchgate. But the problem is i cant not come up with any ideas to make switch from v in and vref controlled by my kits which is included only basic transistors 2en3904,jfet,and some ic like 7474,7485,lm324,counter ls191,bcd display. Dualslope adc architecture a dualslope adc dsadc integrates an unknown input voltage vin for a fixed amount of time tint, then deintegrates tdeint using a known reference voltage vref for a variable amount of time see figure 2. We now consider the single slope and the dual slope adcs. The dual slope adc is an analogtodigital converter that does its conversion using. The singleslope analogtodigital converter ssadc is the most commonly used columnlevel adc for highspeed industrial, complementary metaloxide semiconductor cmosbased xray image sensors because of its small chip area the width of a pixel, its simple circuit structure, and its low power consumption. A columnparallel analogtodigital converter was designed for use with cmos active pixel sensors aps.
However i this was so far the only place to find it. This adc circuit behaves very much like the digital ramp adc, except that the comparator reference voltage is a smooth sawtooth waveform rather than a stairstep. Dual slope adc architecture a dual slope adc ds adc integrates an unknown input voltage v in for a fixed amount of time t int, then deintegrates t deint using a known reference voltage v ref for a variable amount of time. With a dual slope adc you effectively get free averaging as the runup integration phase will have this effect. A block diagram of the circuit figure 1 includes a single primary li cell, a millivoltoutput bridge sensor, a differential amplifier, and the dual slope adc, plus correction circuitry for offset, zero, and span.
The single and dualslope analog to digital converters. Analog to digital conversion and digital to analog converter are described in this ppt. So far, weve only been able to escape the sheer volume of components in the flash converter by using a dac as part of our adc circuitry. This is a decided disadvantage because most real world signals require some smoothing. An adaptable 14bit dual slope adc with wide input range. These adcs are integrating type adc, meaning that they use the integrator for the. Another common adc is the dual slope converter, which relies on integration. One of the many interesting architectures available is the dualslope integrator. An260a 20bit1 ppm linear slopeintegrating ad converter. Integrating adc overview aka ramp and slope adc different flavors, e. Dual slope adc is the best example of an indirect type adc. In the case of the adc, a digital representation of the analog voltage that is applied to the adcs input is outputted, the representation. As the name suggests, a dual slope adc produces an equivalent digital output for a corresponding analog input by using two dual slope technique.
Pdf format this file type includes highresolution graphics and schematics when applicable. I would see this more as a first step to explain the multislope adc, not as a practical enhancement, that would be worth using. In its basic implementation, the dualslope converter, the unknown input voltage is applied to the input of the integrator and allowed to ramp for a fixed time period the runup period. Pdf dual slope adc design from power, speed and area. I walk through this in the video but if you want a chance to work through this handson you can download the.
Our portfolio of adcs offers high speed devices with sampling speeds up to 10. This is done by integrating the unknown for a predetermined length of time. Precise calibration of dualslope adcs application note. Introduction, basic dac techniques, weighted resistor dac, r2r ladder dac, inverted r2r dac, and ic 1408 dac, different types of adcs parallel comparator type adc, counter type adc, successive approximation adc and dual slope adc. If a filter was placed at the input substantial time lag due to settling requirements. The proposed topology can handle both negative and positive input voltage signal with high accuracy. The adaptation in the polarity of the input signal is achieved by exploiting a sign bit in the digital part of the topology. Adc dual slope integrator circuit a fascinating question has always been how can you convert an analog voltage to an equivalent digital word. An integrating adc is a type of analogtodigital converter that converts an unknown input voltage into a digital representation through the use of an integrator. There is a practical and common step in this direction, by having.
A dual slope adc, on the other hand, averages together all the spikes and dips within the integration period, thus providing an output with greater noise immunity. One of the many interesting architectures available is the dual slope integrator. Analogtodigital converter design guide highperformance, standalone ad converters for a variety of embedded systems applications design ideas in this guide are based on many of microchips adc products. Dual slope integrating adc the input signal is applied to an integrator.
Columnparallel dual slope integrating adc pdf version. An alternative ad conversion technique uses the singleslope ad converter. Now the input is integrated for 300ms and the integrated value is 0. The dual slope adc architecture was truly a breakthrough in adcs for high resolution applications such as digital voltmeters dvms, etc. Measurement of active power, electrical energy, and trms. We explain why the slightly more complicated dual slope adc is generally a better choice of adc than the single slope converter. May 05, 2016 i walk through this in the video but if you want a chance to work through this handson you can download the. This paper presents an interesting method using a dual slope analoguetodigital converter ds adc with high resolution to measure the rms value of the current, voltage, active power, and energy for linear and nonlinear loads. Slope integrating adc slope integrating adc the singleslope adc suffers all the disadvantages of the digital ramp adc. Single slope adc architecture dual slope adc architecture. Dual slope converter an integrating adc in which the. Jan 26, 2018 dual slope or integrating type adc watch more videos at lecture by.
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