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INA381: FPGA Current Monitoring via INA381A3IDSGR

Sujith Mohandas
Prodigy 30 points
Part Number: INA381

Tool/software:

Hi Team,

I have designed a system using the INA381A3IDSGR current sense amplifier along with the SmartFusion FPGA (Part number: A2F200M3F-FGG256I). The goal is to monitor the input current through the internal ADC of the FPGA.

Attached are the schematics and FPGA reference PPT for your reference.

My Understanding is by utilizing the VOUT of the INA381A3IDSGR, we can monitor the input current.

My queries is can we connect the VOUT of the INA381A3IDSGR IC directly to the ADC input of the FPGA?

Do we need to add any front-end filter (such as a low-pass filter) between the VOUT of the INA381A3IDSGR and the ADC input pin of the FPGA?

Attachment: /cfs-file/__key/communityserver-discussions-components-files/14/Current-Monitoring-using-Smart-Fusion-FPGA.pptx

Thanks,
Sujith M

  • 0
    TI__Mastermind 22560 points

    Sujith, 

    The answer here is maybe. It will come down to the parameters of the design in terms of how quickly you are looking to sample the device. Do you know if the ADC internal to your FPGA is a SAR or Delta Sigma? I would check out this application note as a starting point. It will walk you through the methodology and mindset if you want to direct drive an ADC with one of our devices. 

    To your question on the filter, as the document will show you, I would definitely recommend a filter, but not necessarily from a filtering standpoint, but more from a charge supplement one.