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oxxyfx

Logic Inverter

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Hello,

I would like to invert the logic on the output of a MAX8211. The output is Low normally but when my battery goes low the Output will go high. I need this signal exactly on the oposite way.

Is there a small device with very few part counts which could do this?

I am googleing around while I am asking this question - but please do reply if you have a solution.

Thanks,

Ox.

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Don't forget the MAX8212 (it is a 8211 with inverted output). As far as inverting the 8211's output so that it works like a 8212, a single transistor will solve that very easily.

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I thought the 8212 is an overvoltage detector. I gotta go back reading this properly. If you are right - and you are always right - I need the 8212 and not the 8211... Then I don't need any additional circuit...

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So, you are right as always - however I have one more question regarding this.

When I turn on this circuit the Max8212 will detect a voltage over the value predetermined by the resistors, so it will supply an "ON" signal on the output. Later when the battery discharges under the predetermined level will the output go "OFF"?

It may sound like a stupid question but the wording on the datasheet says "the max8212 output turns on when the voltage applied to THRESH is greater than the internal reference" - this sounds to me that it defaults to "low" and it will turn "high" when the voltage increases. Will it go "low" if the voltage falls again below the threshold?

Thanks.

Edited by oxxyfx

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When the "output turns on" it means the open drain FET is turned on. This FET sinks current to Gnd. Because is open drain, it cannot source current from V+ (it is up to your external pull-up resistor to do that).

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Ok, I've got the chips - both - and tested them last night. This explanation is only for those confused souls like me, the more professional ones know this by heart:

Max8212 - The out signal is low as long as the voltage applied to the "Vin" pin is higher than the threshold set/calculated by the R1 and R2 resistors. Once the voltage goes below this threshold level, the "Out" pin goes high. You have to pull the "Out" pin high with a 1-10k resistor for this to happen.

Max8211 - The out signal is high as long as the voltage applied to the "Vin" pin is higher than the threshold set/calculated by the R1 and R2 resistors. Once the voltage goes below this threshold level, the "Out" pin goes low. You have to pull the "Out" pin high with a 1-10k resistor for this to happen.

But then again, I am sure you all knew that already :)

Thanks,

Ox.

Edited by oxxyfx

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