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TPS65983B: External MOSFET OCP test

Austin Chen87
Prodigy 30 points
Part Number: TPS65983B

We are using the external MOSFET to support 20V/5A, but I have some questions about OCP test as below:

1.What is the overcurrent timeout setting? Can one have the graphic description?

2.Timeout setting can be set by GUI, could you recommend proper setting?

3.As far as I know that TPS65983 will control external MOSFET to limit output current when OCP occur,but the MOSFET will have large power dissipation(burnout risk) in this period.

   How to select proper MOSFET base on the overcurrent timeout setting?

4.TPS65983 don't know external MOSFET state( ex. heat) in OCP period, how to ensure the MOSFET don't be burnout damaged?

5.Should I use the CC or CR mode to do the OCP test when using electrical load?

  • 0
    TI__Expert 4415 points

    Hi Austin,

    Welcome to E2E world.

    You can refer to an app note TPS6598x OCP Mechanism and Programming Guide, it will help understand OCP response and do the test.

    For the external power path over current timeout period, we would suggest the minimum in the GUI, which is 640us for TPS65983.

    TPS65983 can sense the current on external power path, and you are right that it cannot detect heat of external MOSFET, so you might need to choose a MOSFET with higher SOA according to the maximum current and over current timeout period.

    If it helps and solves your problem, PLEASE select  This resolved my issue  

    Best Regards,

    Hao

     

  • 0 in reply to Hao Wang14
    Prodigy 30 points

    Hi Hao

    Is the over current timeout mechanism still to perform If we do the output short circuit test?

  • 0 in reply to Austin Chen87
    TI__Expert 4415 points

    Hi Austin,

    The OCP mechanism cannot perform short test because the short protection circuit and over current protection circuit inside TPS65983B are different. But the response time for short protection is far shorter than OCP.

    For more information, you could refer to section 9.3.3.9 and 9.3.3.10, the OCP and short protection of external power path is similar with that of PP_HV.

    If it helps and solves your problem, PLEASE select  This resolved my issue  

    Best Regards,

    Hao