how to compare multiple voltages?

[timedate]

Hi, all

I get several (4-16) DC output voltages, all ranging from 0-3.3v.

and I want to compared all these DC, and choose the highest one as the input signal of my next stage.

what kind of devices should I choose? I searched for "multiple voltage comparator" but found nothing.

Thanks

 

[tpetar]

Use as example PIC18F45K22 (can work on 1,8V) which have 28 10-bit ADC channels, take values from channels, compare them and some output pin should switch some MOSFET DC channel on, and other channels turn off.

 

[BradtheRad]

A peak detector could do what you want.

The capacitor automatically charges to whichever is the highest incoming volt level.

This method subtracts a diode drop from all incoming signals. Therefore you should add 0.7 to all of them beforehand, because signals below 0.7 V will get disregarded otherwise.

The transistor can be used to discharge the capacitor. Or install a medium resistance across it, to discharge it gradually.

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[crutschow]

You could use one op amp precision half-wave precision rectifier for each voltage and connect all the Vout's together (with one common load resistor). The ORed output will equal the highest input voltage.

 

[checkmate]

If you need precision, you can string a bank of peak detectors in parallel.
https://en.wikipedia.org/wiki/Precision_rectifier
If precision is not required, and you can roll your own opamp, you could design an opamp with 16 +ve input terminals and get a lousy peak detector.