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INA187: Overload recovery time for unidirectional current sensing

B C
Prodigy 50 points

Part Number: INA187
Other Parts Discussed in Thread: INA293,

Tool/software:

Hello,

I have an existing design that is currently using an INA293A1 as a low side current sense amplifier to increase the negative common mode range for a UCC29002-1 based load sharing circuit.   That circuit is showing some unexpected behavior under light loads and one of the ideas is that the negative overload recovery time of the INA293 might play a role as some of the supplies might be backdriven under light load due to power supply tolerances.  See the link below for more details.

I found that the INA187 does not include this section about overload recovery in its datasheet.  So if I use the INA187 as a unidirectional amplifier by tying the ref pin to the gnd pin, will it operate without this overload recovery time? 

Also for the INA293A1 roughly how long would the recovery time be?  I expect the most negative Vsense the INA293A1 would see would be -10mV, probably less.

 RE: UCC29002: Improving current settling time and expected current waveform behavior 

Thanks

  • 0
    TI__Expert 7430 points

    Hi BC,

    We are not able to say how long the recovery time will be. It is not something we have characterized because it is highly dependent on the overload conditions.

    The INA187 does not make mention of this in the datasheet, but it is the same as any amplifier that has been saturated, there will be an overload recovery delay. We are not able to specify how long this will take. If you want to avoid the overload then you could tie your REF pin to a non-zero voltage such that the -10mV you see will not saturate the amplifier.

    Best,

    Holly