Comparing two voltages in digital circuit

Started by April151, July 19, 2016, 03:56:57 AM

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April151

I have a task that I have two sensors,which bought from TI ,http://www.kynix.com/Detail/1169820/LM77CIMM-3NOPB.htmleach reading a voltage value. I need a circuit to output 1 if the difference between the two readings is smaller than 10% and 0 otherwise.

I can solve it both analogic or digitally. Since I have more experience dealing with digital circuits than analogic ones, I thought about doing the following: Convert the readings to binary and build a circuit which basically uses the formula | (V1 - V2) | / ((V1 + V2)/2) ) and compares it with 0.1. I think there is an easier way of solving this and wanted some help to find it.

Any help will be greatly appreciated.
Great regards,
April151

Digital Larry

I'd say an analog solution is going to be vastly simpler at the expense of some accuracy.

Digital Larry
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cloudscapes

Isn't that what comparators are for? An 8 pin IC and a couple passives should do the trick.
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ElectricDruid

Quote from: Digital Larry on July 19, 2016, 12:24:40 PM
I'd say an analog solution is going to be vastly simpler at the expense of some accuracy.

Unless the inputs are digital, I don't think you'd even lose accuracy. Probably the reverse. Think about the trouble you'd have to take to *maintain* accuracy if you were going via an ADC.

Tom