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TPS2493: MOSFET or gate driver breaks in the event of an over current or short circuit event

Livio Roth
Prodigy 20 points
Part Number: TPS2493


I use part "TPS2493PWR" in following schematic:

Unom = 48V

UOV@48V ≥ 60V                                Overvoltage threshold

UUV = not defined                             Undervoltage threshold

ILimit(nom) = 4.16A                             Steady-state load current

ILimit = 1.2 * ILimit(nom) = 5A

TA(max) = 60°C                                 Max. ambient temperature

TJ(max) = 125°C                                Max. static junction temperature

TJ2(max) = 150°C                              Max. transient junction temperature

Here is my calculation file:               TPS249x_8x_Design_Calculator_REV_B.xlsx

The problem is that the TPS2493 or the MOSFET may break in the event of an overcurrent or short circuit. The fault is that the MOSFET heats up quickly to approx. 80-130°C immediately after the event. I test the outputs with an electronic load. The overcurrent event is triggered as calculated between 4.9-5.2A. The short circuit is also detected correctly.

This circuit part is present 6 times on a PCB. Out of 10 prototypes or 60 circuit parts, approx. 12% of the controller or MOSFET fails on different circuit parts.

Finally, I was able to repair them all by replacing the TPS2493 and MOSFET, sometimes multiply times. I also tried to change the values of the surrounding components. In the end, replacing the components mentioned led to success.

Once the outputs have been tested correctly, they always work.

What I would like to mention about the schematic is that the TVS diode D15 is only present once on a circuit board and is located near the input connection. This means that it is not located directly next to the respective TPS2493 circuit parts.

Thanks for your support.

Best regards,

Livio

  • 0
    TI__Mastermind 41240 points

    Hi Livio,

    Thanks for reaching out. May I know what exact support you are looking for?

  • 0 in reply to Avishek Pal
    Prodigy 20 points

    Hi Avishek,

    thank you for looking at my request.

    I need to solve the problem and would like some help to reduce the failure rate as much as possible. The fact that so many TPS2493 or Mosfets are failing is incomprehensible to me so far. For this reason I have contacted TI to get further support.

    Thank you very much,

    Livio

  • 0
    Prodigy 20 points

    Is there an update for my task? I would be grateful for any help!

  • 0
    Prodigy 20 points

    Is there an update for my task? I would be grateful for any help!

  • 0 in reply to Livio Roth
    TI__Mastermind 41240 points

    Hi Livio,

    Extremely sorry for the delay.

    I am not seeing anything wrong in the schematic and design calculator. 

    Can you please share the part numbers of D15 and D26? I am not able to read from the schematic. 

    At what voltage did you perform overcurrent and short-circuit events? 

  • 0 in reply to Avishek Pal
    Prodigy 20 points

    Hi Avishek,

    many thanks for your support!

    I performed the overcurrent and short-circuit events at V_FCS = 48V.

    D15, D7: SMBJ58AQ-13-F (TVS-Diode,Unidirectional,58V,SMB-2)

    D26: SE50PADHM3/I (Rectifier,200V,5A,DO-221BC-2)

    T9: SIR680DP-T1-RE3 (N-Chanal,80V,100A,PowerPAK-SO-8)

    R37: ERJ-6CWFR010V (10mOhm,0.5W,0805)

    Thank you and best regards,

    Livio

  • 0
    Prodigy 20 points

    Hi Avishek,

    do you have an update for my task?

    Or is there a TI support contact who can take care to my problem/task?

    I don't think we're getting anywhere like this...

    Best regards,

    Livio

  • 0 in reply to Livio Roth
    TI__Mastermind 41240 points

    Hi Livio,

    Sorry for the delay.

    Honestly... I don't find anything wrong in the schematic and design calculator. Is the MOSFET heating up too much? What is the RthJA of the MOSFET in your PCB? I know the data mentioned in the MOSFET datasheet. I'd like to know the experimental value of RthJA in your PCB. Can you measure the peak voltage at VCC pin to ground during the output hot-short? Can you measure the minimum voltage at OUT pin to ground during the output hot-short? Violating the absolute maximum ratings of the VCC and OUT pins can damage the controller. 

    I am wondering if this causes exceeding the VCC pin to GND voltage beyond the absolute maximum rating.  

    "What I would like to mention about the schematic is that the TVS diode D15 is only present once on a circuit board and is located near the input connection. This means that it is not located directly next to the respective TPS2493 circuit parts."