Integrating ADC simulation single and dual slope using op amp

<h2><span style="font-size: large;"><b>Contents:</b></span></h2><ul><li>Introduction to Integrating ADC</li><li>Single slope ADC</li><li>Dual Slope ADC</li><li>Multisim Simulation</li></ul><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://go.ad2up.com/afu.php?id=1070744"><img border="0" height="276" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh15Nmcg-Fx4ZvcQJZsLixcYZSWmaGiludvc0oPQEfvP5eOH-lL6MSrYCLNtaoWotyAnCfRqVZ7Iz-T2EO7WhV-E1vu9VDWSMHM4Q_yzI-K-FAnAU_h5FWfz3Jx-TMLxf5evv-J8WuHEco/s640/mulisi.JPG" width="640" /></a></div><ul></ul><br /><h2><span style="font-size: large;"><b>Introduction to Integrating ADC:</b></span></h2><div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;">Integrating analog-to-digital converters (ADCs) provide high resolution analog-to-digital conversions, with good noise rejection. These ADCs are ideal for digitizing low bandwidth signals, and are used in applications such as digital multi-meters and panel meters. They often include LCD or LED drivers and can be used stand alone without a </span>micro controller<span style="font-family: inherit;"> host.<o:p></o:p></span></span></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;">Integrating analog-to-digital converters (ADCs) provide high resolution and can provide good line frequency and noise rejection. Having started with the ubiquitous 7106, these converters have been around for quite some time. The integrating architecture provides a novel yet straightforward approach to converting a low bandwidth analog signal into its digital representation. These type of converters often include built-in drivers for LCD or LED displays and are found in many portable instrument applications, including digital panel meters and digital multi-meters.</span><span style="font-family: "arial" , sans-serif;"><o:p></o:p></span></span></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;"><br /></span></span></div><div class="MsoNormal" style="background: white; line-height: normal; margin-bottom: 1.5pt; margin-left: 0in; margin-right: 0in; margin-top: 11.25pt; mso-outline-level: 4;"><h2><span style="font-family: inherit;"><span style="font-size: large;"><b>Single-Slope ADC Architecture:</b></span></span></h2></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;"> </span></span></div><div class="MsoNormal"><span style="font-family: inherit;"><span style="background: white; font-size: 12pt; line-height: 107%;">The simplest form of an integrating ADC uses a single-slope architecture. Here, an unknown input voltage is integrated and the value compared against a known reference value. The time it takes for the integrator to trip the comparator is proportional to the unknown voltage (T</span>_{<span style="background: white; font-size: 9pt; line-height: 107%;">INT</span>}<span style="background: white; font-size: 12pt; line-height: 107%;">/V</span>_{<span style="background: white; font-size: 9pt; line-height: 107%;">IN</span>}</span><span style="background: white; font-size: 12pt; line-height: 107%;"><span style="font-family: inherit;">). In this case, the known reference voltage must be stable and accurate to guarantee the accuracy of the measurement.</span><span style="color: #333333; font-family: "arial" , sans-serif;"><o:p></o:p></span></span></div><div class="MsoNormal"><span style="background: white; color: #333333;"><span style="font-family: inherit;"><br /></span></span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6hQJJbLWjO67DEIsJQR_oAm4MYy13VMrMB10OOlCE_El0fvp9ct2WULTYVg0MvVa7_COsObNx9wUCtLO7Z__-vTdiM7sBaDGwIg48scbz0sdg235-hp22zX1MuHZC2OGmffnJk_HWdnI/s1600/wwwwww.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="356" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6hQJJbLWjO67DEIsJQR_oAm4MYy13VMrMB10OOlCE_El0fvp9ct2WULTYVg0MvVa7_COsObNx9wUCtLO7Z__-vTdiM7sBaDGwIg48scbz0sdg235-hp22zX1MuHZC2OGmffnJk_HWdnI/s400/wwwwww.gif" width="400" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;">One drawback to this approach is that the accuracy is also dependent on the tolerances of the integrator's R and C values. Thus in a production environment, slight differences in each component's value change the conversion result and make measurement repeatability quite difficult to attain. To overcome this sensitivity to the component values, the dual-slope integrating architecture is used.<span style="color: #333333;"><o:p></o:p></span></span></span></div><div class="MsoNormal"><span style="background: white; color: #333333;"><span style="font-family: inherit;"><br /></span></span></div><h2 style="background: white; margin-bottom: 1.5pt; margin-left: 0in; margin-right: 0in; margin-top: 11.25pt;"><span style="font-family: inherit;"><span style="font-size: large;">Dual-Slope ADC Architecture:</span></span></h2><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;"> </span></span></div><div class="MsoNormal"><span style="font-family: inherit;"><span style="background: white;">A dual-slope ADC (DS-ADC) integrates an unknown input voltage (V</span>_{<span style="background: white; font-size: 9pt; line-height: 107%;">IN</span>}<span style="background: white;">) for a fixed amount of time (T</span>_{<span style="background: white; font-size: 9pt; line-height: 107%;">INT</span>}<span style="background: white;">), then "de-integrates" (T</span>_{<span style="background: white; font-size: 9pt; line-height: 107%;">DEINT</span>}<span style="background: white;">) using a known reference voltage (V</span>_{<span style="background: white; font-size: 9pt; line-height: 107%;">REF</span>}</span><span style="background: white;"><span style="font-family: inherit;">) for a variable amount of time.</span><span style="color: #333333; font-family: "arial" , sans-serif;"><o:p></o:p></span></span></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;"><br /></span></span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifQPiMOks78mU3ew964NnFYFJ4GZuXUbKOhOqzIBKvoKP3pj6G9zV1Tzb-TcC9AGW2MnGjnlZ-evOhQnaBRLqu4z8chqsI3Vv-tP6u2dcARswppivOhmvx-j30zq4Htr5pzgkm4eQ7x1k/s1600/XCC.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="195" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifQPiMOks78mU3ew964NnFYFJ4GZuXUbKOhOqzIBKvoKP3pj6G9zV1Tzb-TcC9AGW2MnGjnlZ-evOhQnaBRLqu4z8chqsI3Vv-tP6u2dcARswppivOhmvx-j30zq4Htr5pzgkm4eQ7x1k/s400/XCC.gif" width="400" /></a></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;"><br /></span></span></div><div class="MsoNormal"><span style="background: white;"><span style="font-family: inherit;"><br /></span></span></div><div class="MsoNormal"><span style="background: white;"></span></div><div class="MsoNormal"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">The key advantage of this architecture over the single-slope is that the final conversion result is insensitive to errors in the component values. That is, any error introduced by a component value during the integrate cycle will be cancelled out during the de-integrate phase. In equation form:</span><span style="color: #333333; font-family: "arial" , sans-serif;"><br /><br /><span style="background: white;">Vin × T</span></span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">INT</span>}<span class="apple-converted-space"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"> </span></span><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">= V</span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">REF</span>}<span class="apple-converted-space"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"> </span></span><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">× T</span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">DEINT</span>}<span style="color: #333333; font-family: "arial" , sans-serif;"><br /><br /><span style="background: white;">or</span><br /><br /><span style="background: white;">T</span></span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">DEINT</span>}<span class="apple-converted-space"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"> </span></span><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">= T</span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">INT</span>}<span class="apple-converted-space"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"> </span></span><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">× (V</span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">IN</span>}<span class="apple-converted-space"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"> </span></span><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">/ V</span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">REF</span>}<span style="background: white; color: #333333; font-family: "arial" , sans-serif;">)</span><span style="color: #333333; font-family: "arial" , sans-serif;"><br /><br /><span style="background: white;">From this equation, we see that the de-integrate time is proportional to the ratio of V</span></span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">IN</span>}<span class="apple-converted-space"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"> </span></span><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">/ V</span>_{<span style="background: white; color: #333333; font-family: "arial" , sans-serif; font-size: 9.0pt; line-height: 107%;">REF</span>}<span style="background: white; color: #333333; font-family: "arial" , sans-serif;">.<o:p></o:p></span></div><div class="MsoNormal"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"><br /></span></div><h3><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">Circuit specifications:</span></h3><div class="MsoNormal"></div><ol><li><span style="color: #333333; font-family: "arial" , sans-serif;">R=10k, C=0.1uF </span><span style="color: #333333; font-family: "arial" , sans-serif;">and clock frequency=1kHz.</span></li><li>Apply a DC input in range of 0V-1V </li><li>Keep the clock frequency at 1kHz square-wave.</li></ol><br /><div class="MsoNormal"><span style="color: #333333; font-family: "arial" , sans-serif;"><span style="background: white;"></span></span></div><div class="MsoNormal"><br /></div><div class="MsoNormal"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">Now using these formula's calculate the values.<br />Here is the simulation Multisim file.Download it and modify according to your values or you can use same values.</span></div><div class="MsoNormal"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;">Click on Download button after Entering your E-mail address and the download will start automatically.</span></div><div class="mailmunch-forms-widget-446313"></div><div class="MsoNormal"><span style="background: white; color: #333333; font-family: "arial" , sans-serif;"><br /></span></div></div><script data-cfasync="false" src="//p201638.clksite.com/adServe/banners?tid=201638_372770_10&tagid=2" type="text/javascript"></script><br /><br />

Electrical, Electrical Concepts, Multisim

Integrating ADC simulation single and dual slope using op amp

Contents: Introduction to Integrating ADC Single slope ADC Dual Slope ADC Multisim Simulation Introduction to Integrating ADC: Integrating a...