INA199

we are getting a 5-10microSEC pulse on the output when we connect the load. The peak of the spike is 3-4 times what is expected by calculation. After the 5-10microSEC the INA199 opeartes as expected.

1) How can we avoid having this spike?

2) can we use the INA199 as a feedback to a current limit (PWM)?

thank you

zevi

4 Replies

  • Hi Zevi,

    Thank you for posting on the E2E Foruns.

    The INA199 requires a blanking time at startup. Our own tests have shown the device can peak for up to 30uS under some circumstances, when used as a low side sense. The peak is normally not directly related to the measured current, so you would not be able to calculate it.

    Can you elaborate more on current limit feedback required? Cycle by cycle or average? What would the required response time be? What is the PWM frequency?

    Kind Regards,

    Carlos S.

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

  • In reply to Carlos Silva85:

    got it thank you.
    1. we are using the INA199 on the high side with 50:1 gain.
    2. regarding : current limit: cycle by cycle. required response time less 20microSEC,
    what do you see possible?

    thank you
    zevi
  • In reply to zevi kramer35:

    Hi Zevi,

    I would suggest the INA301. It has a dedicated output that can be used to halt the PWM.

    Kind Regards,

    Carlos S.

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

  • In reply to Carlos Silva85:

    got it carlos thank you!