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  1. #1
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    Higher Current Consumption than expected with AFE and embedded Flash

    Hi,

    I am using nRF52840 SoC for my application. A biopotential AFE MAX30003 and Toshiba's 4Gbit embedded flash is used to save the data.
    I have enable the lead off detection and RtoR interrupt in MAX30003. Myapplication reads the FIFO buffer when it gets 18 samples by sensing the interrupt generated. I am storing the data to a buffer and when the buffer reached 2Kbit, I write it into embedded NAND flash. This is the overall flow of my application. I am expecting around 3mA average current for the whole process. But right now I see around 9mA average current. I use Nordic Power Profiler Kit to measure the current.

    Everything works in 1.8V. I use a battery charge controller, TPS62740(step down converter), nRF52840, MAX30003, TC58CYG2S0HRAIG.

    I am attaching the schematic for reference. Is there anything I should consider in hardware design?

    Please help.

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  2. #2
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    Re: Higher Current Consumption than expected with AFE and embedded Flash

    Hi,

    Please confirm that at any time no pin is left floating, neither a used pin nor an unused pin.

    Usually input pins where the voltage level is not close to VCC or GND may cause increased supply current.
    (ICC).

    Klaus
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  3. #3
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    Re: Higher Current Consumption than expected with AFE and embedded Flash

    What is the recommended configuration for those pins?



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    Re: Higher Current Consumption than expected with AFE and embedded Flash

    Hi,

    As already said (and if not otherwise mentioned): close to VCC or close to GND.

    It is written in the datasheet, and I assume the IC manufacturers provide additional information about "low power consumption".
    There are many threads and discussions.

    Klaus
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    Re: Higher Current Consumption than expected with AFE and embedded Flash

    Thanks for the reply. I am seeing a huge current surge. The maximum current I am seeing is around 80mA, which is really high considering the max current of the components used.



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    Re: Higher Current Consumption than expected with AFE and embedded Flash

    I am seeing a huge current surge. The maximum current I am seeing is around 80mA.
    Hard to give less information…

    Where do you see the current peak and when? You should be able to trace the current path down to the component generating the peak.



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    Re: Higher Current Consumption than expected with AFE and embedded Flash

    Thanks, this helped a bit. But would like to know the capacitor and resistor in this application can be a reason for the increased power consumption also TPS62740 ?



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