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INA200: To prevent abnormal current detection

Kazuki Kitajima
Intellectual 1480 points
Part Number: INA200


Hello team,

One of the customers is struggling to use this device correctly.

They have a big capacitor on the load which causes higher inrush current, and protection function works accidentally.

They actually tried to add the 1uF capacitor on the picture below and it seems no problem so far.

So I have two questions about this.

1. Is this potentially the problem for this device or system?

2. Is there any other way to prevent the inrush current?

Thank you,

Kazuki Kitajima

  • 0
    TI__Mastermind 35460 points

    Hi Kazuki Kitajima,

    To answer your two questions:

    1. INA200 output will spike when its power supply ramps. However, if the supply is stable when the issue was observed, then it is more likely a system behavior/problem than a device problem.
    2. With the cap, the spike caused by inrush current is suppressed to the point where it is no longer able to trip the comparator. So this is a viable solution. Of course if the inrush current can be reduced or eliminated, that would be ideal. There are potentially other solutions, but I think the least intrusive option is to move the sense resistor to the downstream of the big cap. Doing so will move it out of the charge current path, theoretically this problem should go away. This doesn’t eliminate the inrush current per se, but it does from the INA200’s perspective.

    Regards, Guang

  • 0 in reply to Guang Zhou
    TI__Intellectual 1480 points

    Guang-san,

    Thank you for answering the questions!

    Best Regards,

    Kazuki Kitajima