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INA226: INA226 interface protocol version

Mark Chen52
Expert 8155 points
Part Number: INA226


Hi, 

Due to customer would like to know the version of I2C and SMBus interface for INA226, they are worry about the if have any problem to communication under different version.

Regards,

Mark

  • 0
    TI__Mastermind 26865 points

    Hello Mark,

    The best way to check compatibility with your I2C and SMBus interface is to look at the timing requirements specified in the datasheet and make sure that your bus falls within those requirements. 

  • 0 in reply to Mitch M
    TI__Mastermind 26865 points

    Oh, and also make sure it works with the voltage logic levels.

  • 0 in reply to Mitch M
    TI__Expert 8155 points

    Hi Mitch,

    Attached is INA226 circuit, please help review it for customer.

    BTW, could you help to confirm if we need to program below register from BMC before sensing starting ?

    TI_INA226_20211123.pdf

    1. select the resolution of the Current Register (04h): Current_LSB.
    2. configure the Calibration Register (05h)
    3. Any other Register need write value base on our application too?

    Regards,

    Mark

  • +1 in reply to Mark Chen52
    TI__Expert 4720 points

    Hello Mark,

    Mitch is currently away I will be helping you if it is fine. 

    The max current you can calculate with the INA226 with 2mOhm is 40.96 A, because you are using a 1 watt resistor the max current measurable will be 22.3 A (limiting factor being the power of the rshunt). If this max current is ok then the rshunt is fine. Make sure you have pull-up resistors on the SDA and SCL line.

    1. Yes, you can change the resolution of the vshunt register, vbus register, set number of averages, and configure which mode to work in. If left default you will get least number of averages and a conversion time of 1.1 ms for the measurement of the vshunt and vbus register. It will work in continuous mode for both registers. This is done in the configuration register (0x00). Note the current register is based on the vshunt register so select the appropriate configuration for the vshunt to ensure enough resolution for the current measurement.

    2.. Yes you should program the value calculated using eq. 1 and 2 from datasheet pg. 15.

    3. I am unsure of your application but the INA226 comes with the ability to set a limit and alert when those limits are breached. Using the Mask/Enable register various limits can be placed, as well as other features like current polarity and conversion ready (if using the device in trigger mode). Using the alert limit register programming in a value will alert based on the Mask/Enable bit register settings. 

    If you have any questions please reply

    Regards,

    Castrense