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INA293-Q1: In phase current measurement?

Sebastian Siegfried
Intellectual 680 points
Part Number: INA293-Q1
Other Parts Discussed in Thread: INA240, INA293, DRV8323, INA241B, INA180, INA281

Hi

Is it possible to measure the phase currents of a three phase motor control application with the INA293-Q1? I used the INA240 before and this part is not available anymore and it seems the INA293-Q1 is better in all terms, also the CMRR. It is not adverted in the datasheet to do so, but I could not find anything that would not allow it?

What I could not find in the INA293-Q1 datasheet is, if it can measure the current bidirectional? I think that is the main difference here, since it seems it cannot measure it bidirectional.

Kind Regards,
Sebastian

  • +1
    TI__Mastermind 29280 points

    Hello Sebastian,

    Even though the CMRR is better the INA293 is unidirectional.  Also the INA293 does not have the PWM rejection circuitry.  So if you are doing inline sensing it will not work( see www.ti.com/lit/an/sboa172/sboa172.pdf) .  For high or low side sensing it will work but keep in mind that the bandwidth of the INA293 does drop a little when the Vsense/Vout is low.  We do have the INA241 but it is in preview mode and not orderable for large orders yet.

    Regards,

    Javier

  • 0 in reply to Javier Contreras4
    Intellectual 680 points

    Thanks about that. I'm looking for a current measurement amplifier for low side measurement, like the integrated amplifier in the DRV8323, but I cannot find something equivalent, especially in terms of price. What kind of amplifiers are inside the DRV8323? 

  • 0 in reply to Sebastian Siegfried
    TI__Mastermind 29280 points

    Hello Sebastian,

    Normally a stand-alone CSA, current sense amplifiers will be more accurate and you can see that if you look at two major specifications of offset and gain error.  The other issue is the negative spike at the input seen from the drive of the motor.  We have a INA180 which is budget friendly but you need to add some current limiting at the input with transient spikes below -0.3V at the inputs.  The other option is the INA281 or our future part currently in preview INA241B and both these parts can have the VCM go below GND much move than the INA180.