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TPS25983: TPS25983xO

yuan hui Su
Prodigy 30 points
Part Number: TPS25983
Other Parts Discussed in Thread: CSD18511Q5A

Tool/software:

Our application has a rated input of 12V (9-16V) and a rated current of 10A. We plan to use TPS25983xO to achieve protection against overcurrent, overvoltage, and reverse power supply.
If according to the instructions in Figure 7-8 of the data sheet, adding Qb FET externally can achieve reverse current protection. My question is, can this also achieve reverse power protection? When the external power supply is plugged in, the positive and negative poles of the power supply are reversed
Thank you!

  • 0
    TI__Mastermind 39045 points

    Hi Yuan Hui Su,

    The external BFET can only provide you RCB when device is off.

    If you need reverse polarity protection (as you described it above), you will have to add a diode from device ground to power ground. Similar to this example.

    Best Regards,
    Arush

  • 0 in reply to Arush Gupta
    Prodigy 30 points

    Hi Arush，
    Thank you for your feedback!
    In the layout example in the data manual, there is a short circuit between the signal ground island and the power ground. Is it feasible to place the reverse polarity diode you mentioned at this position?
    Thank you!

  • 0 in reply to Arush Gupta
    Prodigy 30 points

    Hi Arush，

    Another question, I noticed that the illustration you posted is TPS25942x, which has back-to-back FETs inside, while in the illustration of TPS25983, there is only one FET inside.

    Does this mean that in order to achieve reverse polarity protection of the power supply, in addition to installing a grounded diode, an external Qb FET is still needed (even if reverse current protection is not required)?


    Thank you!

  • 0 in reply to yuan hui Su
    TI__Mastermind 39045 points

    Hi Yuan Hui Su,

    The illustration shared above looks good.

    back-to-back FET don't have any relation here for input side reverse polarity protection. By placing the diode, we are preventing any current flow from GND to different pins.

    Best regards,
    Arush

  • 0 in reply to Arush Gupta
    Prodigy 30 points

    Hi Arush，

    Based on the previous discussion, I will design the circuit according to the attached diagram. Do you think it is feasible? Could you please help recommend the models of Qb FET and additional RPP signal diode.


    Thank you!

  • +1 in reply to yuan hui Su
    TI__Mastermind 39045 points

    Hi Yuan hui san,

    I apologies for delay. I missed this thread. Most likely you might have already found these parts but I will just add some other 

    We use CSD18511Q5A in our EVM with 1.13Ohms Rg. 30V FET can also be used. The Vgs max should be >= 10V. 

    For the RPP signal diode, any PN junction diode with appropriate breakdown voltage should be fine here.  

    Best regards,
    Arush