Timeline for How do I amplify a 0-100mV signal to an ADC with a range from 0 to a specific reference voltage?
Current License: CC BY-SA 3.0
11 events
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| Nov 3, 2016 at 20:22 | comment | added | iheanyi | @Anthony, I just realized you want to use an in-amp so this may not be an option (because you need to control feedback). Using an op-amp (to build a difference amplifier), you can add an offset to your signal: See en.wikipedia.org/wiki/… Here, you'd connect Rg to the offset rather than ground. To generate the offset, a voltage divider is sufficient. With Rg == Rf, Vout = Voff + (Rf / R1)*(V2 - V1) | |
| Nov 2, 2016 at 18:46 | vote | accept | Anthony | ||
| Nov 1, 2016 at 23:22 | comment | added | Anthony | @iheanyi, at this point that is the much simpler option with much easier to calculate error. I don't have a strong requirement to use the full range. What's the best way to add that offset? I'm having a hard time wrapping my head around it. | |
| Nov 1, 2016 at 22:56 | comment | added | iheanyi | Why not add an offset to the input of the amp, which makes the output 10mV when the input signal is 0? You'd lose dynamic range on the signal (because you'd need the output to still over the full 0-100mV swing), but then get away with just using the amplifier. Is there a strong requirement to use the full range of the ADC? | |
| Nov 1, 2016 at 21:00 | comment | added | Anthony | I read that the 328p can't use an AREF below 1V. Also, this isn't the only range that I need and while AREF can be switched, I'd rather not. | |
| Nov 1, 2016 at 19:28 | comment | added | Eric Johnson | Is there a reason that you can not just put 100mv into the AREF pin for the ADC? (28.5.2 in datasheet) | |
| Nov 1, 2016 at 18:07 | history | tweeted | twitter.com/StackElectronix/status/793514891273498624 | ||
| Nov 1, 2016 at 13:12 | answer | added | Spehro 'speff' Pefhany | timeline score: 4 | |
| Nov 1, 2016 at 12:56 | answer | added | Andy aka | timeline score: 7 | |
| Nov 1, 2016 at 12:40 | answer | added | Olin Lathrop | timeline score: 8 | |
| Nov 1, 2016 at 12:20 | history | asked | Anthony | CC BY-SA 3.0 |