Analog digital wandler mit zahler vereinfacht youtube. Working of dual slope adc is discussed in this video. 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. An260a 20bit1 ppm linear slopeintegrating ad converter. An answer to this calibration drift dilemma is found in a design variation called the dualslope converter.
The main purpose was to construct a 16bit dual slope ad converter with an input voltage of 5v. 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. Dual slope adc is the best example of an indirect type adc. Both adcs make use of simple opamp circuits and control logic to do most of their work. Dec 11, 2014 if the slope here means the slope of the transfer characteristic, it would be closely related to the linearity, gain and monotonous characteristic of the adc. How analogtodigital converter adc works hardware secrets. Unlike a dualslope,this converter has no inherent noise rejection capability. Procedia engineering 47 2012 997 a 18777058 2012 the authors. Since we started the second integration at the value produced by the first vint and waited until it became zero, we can establish that the areas under the two curves are equal. In the dualslope converter, an integrator circuit is driven positive and negative in alternating cycles to ramp down and then up, rather than being reset to 0 volts at the end of every cycle.
Follow 6 views last 30 days marceljoseph etoga on 10 oct 20. 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. In the dual slope converter, an integrator circuit is driven positive and negative in alternating cycles to ramp down and then up, rather than being reset to 0 volts at the end of every cycle. Adc converts the quantities of real world phenomenon in to digital language which is used in control systems, data computing, data transmission and information processing. It is pretty slow, but its ability to reject highfrequency noise and fixed low frequencies such as 50 hz or 60 hz makes it. You can think of this method as a stop watch of sorts. The smallest input step that can be resolved by the adc is the lsb least significant. The tc500 is the base 16bit max device and requires both positive and negative power supplies. In this video, the working of the successive approximation type adc is explained using the example of 4bit adc. Comparision of different types of adcdigital voltmeter 7. With a dual slope adc you effectively get free averaging as the runup integration phase will have this effect. We explain why the slightly more complicated dualslope adc is generally a better choice of adc than the singleslope converter.
A dualslope adc dsadc integrates an unknown input voltage vin for a fixed amount of time t. Dual slope type adc analogintegratedcircuits electronics tutorial. We now consider the singleslope and the dualslope adcs. 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. Therefore, the columnparallel single slope architecture fig. This adc was characterised by many metrological advantages, but could be put into practical use only in the 1970s, when the technology of semiconductor devices achieved a sufficient level. An internal reference dac that, for comparison with vref, supplies the comparator with an analog voltage equal to the digital code output of the sarin. Figure5 depicts block diagram of dual slope integrating type adc. An adaptable 14bit dual slope adc with wide input range. An integrating adc dual slope adc applies the analog input voltage to the input of an integrator and allows the voltage to ramp for a fixed time period the runup period. It is pretty slow, but its ability to reject highfrequency noise and fixed low frequencies such as. 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.
A modulator converts the input analog signal into digital bit. One of the most common analogtodigital converters used in applications requiring a sampling rate under 10 msps is the successive approximation register. One of the many interesting architectures available is the dual slope integrator. An alternative ad conversion technique uses the singleslope ad converter. This greatly decreases the area necessary to implement the adc. So, realworld signals must be converted into digital, using a circuit called adc analogtodigital converter, before they can be. One of the many interesting architectures available is the dualslope integrator. Two principal advantages of the dualslope adc are its. Adc a\d converter types converters flash adc delta. The time on the dial is proportional to the input voltage. An analog to digital converter adc is an electronic device which converts varying analog signals into digital signals so that they can easily be read by the digital devices. Apr 27, 2019 an integrating adc dual slope adc applies the analog input voltage to the input of an integrator and allows the voltage to ramp for a fixed time period the runup period. The peak value attained contains the only clue but that is unknown to this type of adc.
In this chapter we will use software trigger mode, so the actual sampling rate is determined by. For n bit dual slop type of adc, vr 2 n n va total time for conversion of input va is expressed as follows. As a minimum, each device contains the integrator, zero crossing comparator and proc essor interface logic. Integrating adcs ece614 advanced analog ic design presented by antonio oblea may 7, 2008. An integrating adc is a type of analog todigital converter that converts an unknown input voltage into a digital representation through the use of an integrator. 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. Simply count the time it takes for the integrator voltage to ramp back down to zero volts. 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. In this animation, you control the analog signal by dragging the handle on the left. Labview application for computer simulation of the. Then a known reference voltage of opposite polarity is applied to the integrator and is allowed to ramp until the integrator output returns to zero the rundown period. The name dual slope comes from its basic behavior of creating a waveform with a positive slope, followed by a negative slope. Analog to digital converter how adc works with pic mcu. How adc works, their types, dual slope, successive.
As the name suggests, a dual slope adc produces an equivalent digital output for a corresponding analog input by using two dual slope technique. Difference between adc typescounter,flash,sar,dual slope. In dual slope type adc, the integrator generates two different ramps, one with the known analog input voltage va and another with a known reference voltage. 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. Dual slope adc design from power, speed and area perspectives. With a dualslope adc you effectively get free averaging as the runup integration phase will have this effect. 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. Ald manufacturers,suppliers adc processors,controllers,ad convertor in sunnyvale. The dualslope analogtodigital converter adc, invented in 1957 by gilbert, was an excellent circuit dedicated for signal conditioning and measuring purposes. A sigmadelta adc has a modulator and a digital filter also called as decimation filter as shown in fig. 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.
An answer to this calibration drift dilemma is found in a design variation called the dual slope converter. Dual slope or integrating type adc watch more videos at videotutorialsindex. Our portfolio of adcs offers high speed devices with sampling speeds up to 10. Comparision of different types of adc digital voltmeter 7. The purpose of this work was to understudy the functionalities as well as the operations of the various converters adda converters with emphasis laid on the dual slope adcs. Sigmadelta analogtodigital converter adc is used in many application including telecommunications for analog to digital conversion. Dual slope adcs are used in applications demanding high accuracy. This is a decided disadvantage because most real world signals require some smoothing. Single slope and dual slope adc explained duration. We now consider the single slope and the dual slope adcs. We explain why the slightly more complicated dual slope adc is generally a better choice of adc than the single slope converter. Icl7106 internal structure half flash adc application of dual slope adc dual slope adc an2094 app2094 icl7106 max153 text.
This analog todigital converter adc has been at the heart of the digital volt meter dvm for decades. The single and dualslope analog to digital converters. Write the disadvantage of single slope integrator adc. What is analog to digital converter, how to convert analog signal into digital. Sigmadelta analogtodigital converter electricalvoice. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Precise calibration of dualslope adcs application note. Integrating or dual slope adc analog to digital converter. Dashed lines mean control to throw a switch or convey a pulse. 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. However, it generally has a long conversion time, so we propose an innovative. The ex input signal is directly coupled to the comparator input with no filtering. I have read up about the integrator circuit and think i know how it works.
Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. The basic dna of this converter is your basic op amp integrator, two switches and a reference. Aug 24, 2017 sigmadelta analogtodigital converter adc is used in many application including telecommunications for analog to digital conversion. The output is also extremely simple, just a pulse that needs to be timed which can be done with even the simplest micro controllers. If a filter was placed at the input substantial time lag due to settling requirements. This note explains the use of offset flipping for onthefly calibration of the adc. The dual slope adc dsadc is a type of analogtodigital conversion with low input bandwidths. An alternative ad conversion technique uses the single slope ad converter. Dualslope adc analysis rc v t dt r v c v in t in c 1 1 0 1 1. Follow 7 views last 30 days marceljoseph etoga on 10 oct 20. Aug 08, 2014 one of the many interesting architectures available is the dual slope integrator. The dualslope conversion improvement radojle radetic1, marijana pavlovkagadejev2, nikola milivojevic3 abstract.
Just a few basic components constructs this basic adc implementation. Ad converter types converters flash adc deltasigma adc dual slope integrating adc successive approximation adc 2 bitweighing conversion uses a comparator to weigh the applied input against the output of an nbit da converter. The dual slope analogtodigital converter adc, invented in 1957 by gilbert, was an excellent circuit dedicated for signal conditioning and measuring purposes. At the end of this interval, a known reference voltage v r of opposite polarity is applied to the integrator. Understanding the successive approximation register adc. Two consecutive integration periods yields two slopes. Analogtodigital converters adcs translate analog signals into digital values for use in processing and control systems. This clever analogtodigital converter adc has been at the heart of the digital volt meter dvm for decades. How deltasigma adcs work, part 1 texas instruments. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. The block diagram of a dual slope adc is shown in the following figure. Well leave out the details of the countercontroller. Mar 11, 2017 integrating or dual slope adc analog to digital converter. Another common adc is the dual slope converter, which relies on integration.
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