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Original question:

DRV8701: About DRV8701 SO Signal

DRV8701: DRV8701E

Pritesh Metha
Prodigy 190 points
Part Number: DRV8701
Other Parts Discussed in Thread: DRV8703-Q1, OPA365

Hi,

I am using DRV8701E to drive 60A current rating motor by connecting mosfet in parallell. Everything works as expected.Now i want to monitor current using SP and SN across current sense resistor of 250 uOhm

value.SO pin is connected to ADC pin of controller.

Will this connection work because drop across is in sense is few micro or mili volt.

  • 0
    TI__Guru** 114905 points

    Hi Pritesh,

    The connection will work, but may not be satisfactory due to the voltage range of SO.

    The SO output will vary from 0V at no current to 300mV at 60A.

    Using a larger sense resistor can help. A 1mOhm can increase the range from 0 to 1.2V, but the wattage will increase.

    Other options are to use the DRV8703-Q1 (SPI controlled gain up to 80) or an external amplifier to set the desired gain.

  • 0 in reply to Rick Duncan
    Prodigy 190 points

    Hi Rick ,

    Can you please suggest an external amplifier to set the desired gain.So will connect that amplifier output to ADC pin of my controller.

  • 0 in reply to Pritesh Metha
    TI__Guru** 114905 points

    Hi Pritesh,

    There are many to choose from. May I suggest beginning your search here:

    Please use the link as a starting to determine the best match for your application.Once you have one or two based on performance, features, and cost, please ask for additional help.

    FYI -- We have used the OPA365 on past evaluation boards.