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INA226: Some quesitons

Shu-Cheng LIN
Guru 11785 points
Part Number: INA226
Other Parts Discussed in Thread: INA209

Hi Sirs,

Sorry to bother you.

We would like to know does INA226 can do power limit function? how many the response time?

On INA226 Alert signal, is possible be issued when the power limit is triggered? How many the response time?

Thanks!!

  • 0
    TI__Mastermind 34220 points

    Hi,

    Both these questions are answered by datasheet section 7.3.1.2.

    1 - Yes, Alert pin can be configured to reflect Power Over Limit. A single register X’06 is used to select this functionality.

    Regardless of number of averaging, as soon as there is a single over limit event in power, the Alert pin will trigger. The response time is the Shunt Voltage conversion time plus the Bus Voltage conversion time.

    2 - If you configure both to be 1.1mS (by default) then the response time would be 2.2mS. The shortest possible response time is 280uS if both conversions are set to be 140uS each.

    Regards, Guang

  • 0 in reply to Guang Zhou
    Guru 11785 points

    Hi Sirs,

    Thanks for your quick reply.

    One more question, how long does INA226 take to send an Alert signal from sense to power limit? (The Fastest value)

    Is it possible to set this time? if yes, where is it?

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 34220 points

    Hi,

    Power value is compared with Power Limit as soon as I and V conversion finishes. In case of an over-limit event, the Alert register is set. The transfer of data from Alert register to Alert pin takes one or two system clock delays and should be on the order of a few tens of nS. These delays cannot be set by user.

    Further, the Alert pin is open drain, so the portion of the response time from the moment the output NMOS gate goes high, till the moment the Alert pin reaches low is dependent on the pull up resistor for a given device.

    Regardless, the overall response time, from the moment an over-limit event occurs to the moment Alert pin activates, is dominated by the conversion time which is a few 100uS at least. Other delay components should be negligible.

    Regards, Guang

  • 0 in reply to Guang Zhou
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    From the datasheet, looks the minimum setting of conversion time is 140us. Is mean each voltage and current conversion needs 140us , the total is 280us? or all of them only need 140us;
    By the way we would like to know does TI have similar to power limit function but more faster response solution?

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 34220 points

    Hi,

    The power conversion time would be 280uS max for the fastest configuration.

    Currently in production, we have a number of similar digital devices, INA209 is close to INA226 – with Alert pin and a number of additional features. INA209 has a faster conversion option:

    Regards, Guang

  • 0 in reply to Guang Zhou
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply

    Unfortunately INA209 size is too big. So is there a smaller size solution? same as INA226 will better.

  • 0 in reply to Shu-Cheng LIN
    Guru 11785 points

    Hi Sirs,

    Sorry for pushed, any update on this case?

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Mastermind 34220 points

    Hi,

    Sorry we currently don’t have in production a similar device that is faster than IN226, with Alert pin and in a similar or smaller package.

    Regards, Guang