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INA260EVM: Sampling rate for current sense

Takashi Yamaguchi
Genius 13700 points
Part Number: INA260EVM
Other Parts Discussed in Thread: INA260

Hi team,

My customer is sensing a current using INA260EVM. Could you help with the question below?

The customer enables  "Continuously Poll Data" to read output resister continuously.  However, the sensing interval is around 1sec. Customer would like to take the instantaneous current value. Is there a way to increase the sensing speed?

Regards,

Yamaguchi

  • 0
    TI__Mastermind 26335 points

    Hello Takashi,

    Thanks for using our forum.  If your speed is only limited by the measurement time and not the I2C communication speed, then there are three different configuration settings you can adjust to get a reading faster.  The first is the operating mode.  By selecting "shunt voltage continuous", the current measurements should continuously run with no bus voltage measurements in between.  The other settings include Averaging mode and the shunt conversion time.  If only shunt voltage is measured, then the time to get a measurement for read back is the (shunt conversion time) x (averaging mode number).  If you are also monitoring the bus for power calculations, then the time between each measurement is:( shunt conversion time) x (averaging mode number) + (Bus conversion time) x (averaging mode number).

  • 0 in reply to Patrick Simmons
    TI__Genius 13700 points

    Hi Patrick,

    Thanks for your support.  Customer tried the solution you mentioned but it seems to be still displayed 1sec cycle by enabling Continuously Poll Data as shown below. Is it possible to change the read cycle faster?

    Regards,

    Yamaguchi

  • 0 in reply to Takashi Yamaguchi
    TI__Mastermind 27715 points

    Hi Yamaguchi-san,

    There is a hardware limitation of the SM-USB-DIG controller used for this EVM. It is inherently slower for its communication and data transfer over USB than the INA260 device. This is one of the reasons we are moving to a higher-performance motherboard for new digital EVMs.

    However, if you are referencing the plot, the x-axis may be showing samples instead of time. Patrick, can you please verify this?

    Best regards,

    Ian Williams
    Applications Manager
    Current Sensing

  • 0 in reply to Ian Williams
    TI__Mastermind 26335 points

    Hello Takashi,

    I took a closer look at the EVM GUI we have and it looks like the default program gets 1 measurement per second regardless of what setting is chosen.  Sorry I didnt catch that limitation on the first reply.  I will need to check with my team, but I do not think there is a way to unlock the code to modify this setting.  Even if you were able to modify the setting in the GUI code, I think you might still run into the communication limitation of the SM-USB-DIG controller that Ian noted above.  If your customer needs to read measurements quicker from the INA260, it might be easier to use a microcontroller to read from the device.  If your customer was planning on integrating this or some other current monitor into their system board, they might already have a microcontroller readily available and have written some code for an i2c communication read routine.  If they have neither, you might want to sync up with the microcontroller team and see what they might recommend.