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AFE0064: Vint_off of AFE0064

Chenkai Wang
Prodigy 190 points
Part Number: AFE0064

Hi, we are thinking about using AFE0064 to detect our current signals with both positive and negative polarities. I found that by applying voltages at pin 56 and pin 57, it is possible to detect both positive and negative currents (Figure 10). I want to ask if it is possible to apply certain voltages at pin 56 and 57, such that Vint_off in Figure 10 is in the middle of REFP and REFM. In this case, the detection ranges for positive and negative currents are equal. If not, what is the limit of Vint_off that I can set? Thank you!

  • 0
    TI__Mastermind 49756 points

    Hello Kane,

    I have sent you an email requesting additional details about the customer.

  • 0
    TI__Prodigy 620 points

    Hi,

    yes, you can add offset charge to keep integrator output at the middle of operating range. That way, input signal charge can have either polarity without integrator saturation.

    To achieve this, add offset charge equal to half of full-scale charge range. For example, if you are using 2.4 pC charge range, then you need to add 1.2pC offset charge. This can be achieved by applying V = 0.28 V at pins 56,57.