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TPS61240: Step-Up DC/DC Converter getting heated suddenly

Ali Rumane
Prodigy 20 points
Part Number: TPS61240

Hi,

I am using step-up converter TPS61240DRVR to step up 3.7V from the battery to 5V which is required for my application. I referred datasheet and made a schematic, after getting PCB, it was working for around 3-4 months until suddenly other day battery become swollen. The device was with the software team who have no idea about hardware immediately disconnected the battery and left it over.

After disposing of the battery, I took the fresh battery and connected it to the board after found that the board was heated and found the step-up converter was very hot. I removed the battery, took a new board and connected the battery but again it was hot on the new board.

I thought it must be a battery issue, changed a battery again, tried previous battery on some other application board and battery was working fine. I have a single side battery input connector so there is the least possibility I might have connected the battery with the reversed polarity.

Also do I need to pulldown EN pin to ground with pulldown resistor as it is enabled and disabled form microcontroller pin for now?

What could be a possible reason for the same?

Can you please let me know how to debug the issue?

  • 0
    TI__Mastermind 34201 points

    Hi Ali,

    What's the Iout of this application?

    The schematic looks good. For layout, it's better to use wider trace between inductor and SW pin.

    Have you ever used oscilloscope to probe SW, Vout, Vin waveform?

  • 0 in reply to Zack Liu
    Prodigy 20 points

    Zack Liu said:
    Iout of this application

    It is around 50mA.

    Zack Liu said:
    it's better to use wider trace between inductor and SW pin

    Thank you for your suggestion, I will do that.

    Zack Liu said:
    Have you ever used oscilloscope to probe SW, Vout, Vin waveform?

    Is it okay to view the waveform while the board is hot? It immediately heats within 5s after powerup.

    Also, do I need to pulldown EN pin to ground with pulldown resistor as it is enabled and disabled form microcontroller pin for now. I am editing the question with this query.

  • 0 in reply to Ali Rumane
    TI__Mastermind 34201 points

    Hi Ali,

    It's totally ok to view the waveform as long as the board is still working, no matter how hot it is.

    Pulldown resistor is not necessary because MCU IO pin is logic low when it's disabled.