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DDC264 Measuring positive and negative currents

JONATHAN VIVENTI
Prodigy 60 points
Other Parts Discussed in Thread: DDC264, AFE0256, AFE0064

Hi,

Is there any way to configure the DDC264 to measure equal amounts of positive and negative currents? I.e. integrating electrons and holes? 

It seems like there are ways to do this with the AFE0064 and AFE0256, such as with the charge dump or charge compensation schemes. Are any other parts able to do this? 

More generally, I would like a part that can measure many low level currents (or voltages), at least 16-32 per package, that are equally likely positive and negative. The input voltage can be biased to any level, however the net current has to be average 0. 

Thanks,

Jon 

  • 0
    TI__Expert 4680 points

    Hi Jon,

    Sorry, but the DDC can only measure positive (going into the device) currents. It can actually measure very small outgoing, but only 0.4% of the range, so, I don’t think that will work for you...

    The other way that has been suggested in the past is to add a large resistor (10M) in the input to a given positive voltage so to create a DC current that would offset your negative current. I.e., that current has to be as big as your biggest negative current. I think that may work (that is actually how we test for linearity for the positive ranges) but it is probably bulky. We do not have any internal example where we have done that...

    Best regards,

    Eduardo