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INA293: Saturation to Active current measurement- Recovery time

Meenalochini D
Prodigy 150 points
Part Number: INA293

Hi Team,

Our requirement is to measure the 1mA-4A current with 1mA accuracy with the Rsense of 25mohm.

We were planning to use INA293A5 current sense amplifier for 0.5mA-240mA current range and INA293A1 current sense amplifier for 240mA-4A current range.

Most of the time, INA293A5 device will be in saturation mode ie.>270mA and during lower current measurement it needs to changed to active mode(amplifier).

What is the maximum time that INA293A5 will take to change from saturation mode to active mode.

Request you to share your response.

  • +1
    TI__Mastermind 29710 points

    Hello Meenalochini,

    This will depend on your application and levels of overdrive you have.  We have some test that give about 15µs but this does depend on the overload condition and recovery you have.  I would place the INA293A5 in your worst application condition of 100mV = 4A*25mΩ then transition to linear range of 2.5mV = 100mA*25mΩ.  I would also give extra time margin as this value will be different for each device.

    Another issue is your swing low as we mentioned before in another of your post.  Below is a circuit below that you can use.  You would need to calibrate the offset and know that it will create a gain error.  For R1 you will notice with 0A your potential output is 41.5mV which is above swing low and above any VOS concerns.  There will be a trade off in the size of R1 and your offset and gain error you will observe.