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Original question:

TPS4H000-Q1: question about how to calculate td(match)

TPS2H160-Q1: switch turn off when driving capacitive load

Elec Cheng
Expert 7055 points
Part Number: TPS2H160-Q1

Hi Expert,

When high side switch drives capacitive load and turn off,  the cap need to discharge. I suppose the cap cannot discharge through MOSFET body diode since the Vbb > Vout still. The cap will discharge via other path, right?

And I see in datasheet that the high side will not act to inverse current even when disabled. The inverse current will flow through body diode. Will this cause some damage to the MOSFET or chip? Thanks.

BR,

Elec Cheng

  • 0
    TI__Genius 16390 points

    Hi Elec,

    Like you mentioned, the cap discharge will not go through the body diode or the FET itself, and it will likely discharged to the load resistance and other parasitic path.

    For the inverse current (I assume this is a separate question), as long as the current is small (not to overheat the FET because diode voltage drop * current), the FET should not be damaged.

    Regards,

    Yichi

  • 0 in reply to Yichi Zhang.
    TI__Expert 7055 points

    Hi Yichi,

    Yichi Zhang. said:
    For the inverse current (I assume this is a separate question), as long as the current is small (not to overheat the FET because diode voltage drop * current), the FET should not be damaged

    So if the inverse is large, it's still possible to damage the FET, right? To avoid this, do we have device that will automatically turn on FET when detecting large inverse current? Just want to discuss with you, is this an applicable way to avoid this? Thanks a lot!

    BR,

    Elec Cheng

  • 0 in reply to Elec Cheng
    TI__Genius 16390 points

    Hi Elec,

    For most of TPSXHBXXX devices we will turn on the FET automatically during a reverse battery events. But please check each datasheet to be sure if that's the case. Let me know if you have further questions. Thanks!

    Regards,

    Yichi