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  • TI Thinks Resolved

TPS63030: TPS63030 extreme current draw from EN pin (>50ma)

Prodigy 80 points

Replies: 14

Views: 183

Part Number: TPS63030

Hello, i have the following circuit

which is pretty much a copy of the one in the datasheet, with a small difference, the enable line is externally driven, in this case an atmega328p, interestingly when activating the en pin, not only the signal didn't activate

the voltage on the line was 0.8v, when shorting it to a 3v3 rail it started working, so i took a multimeter and measured the current going into EN pin, turned out to be around 50ma!

moreover, this is not an isolated case, i have repeated the measurements on 4 devices, and in all of them the same happens

normally i'd think this means a perforated fet, however i can be sure the voltage never went above 4.5v on any pin, hence being well within specification

the truth is that im quite out of ideas, this is an excedengly simple circuit yet it's giving a pretty surprising problem

any help is appreciated

  • In reply to Brigitte:

    Brigitte im aware of that, what I don't know and is baffling me is that the chips are systematically breaking and the maximum voltage possible in the whole system is 4.8v, also there is an other supply which has the same max voltage ratings and works perfectly

  • In reply to diego guglielmi1:

    Hello Diego,

    It is possible that you create overshoots above 4.8V and undershoots below GND in such a system when connecting cables to the board. These voltages can be a lot higher and lower than you would imagine if you never looked at them.

    You could minimize the issue for example with a series resistor on this pin. Then the ringing that happens during connecting the Arduino will be reduced.

    This pin is a high-impedance node and good design practice for high impedance nodes is to terminate it in general. But this is nothing specific to this pin, it is just good design practice to terminate all high-impedance input pins in a design.

    Best regards,
    Brigitte

    For more information on buck-boost devices have a look at www.ti.com/buckboost

  • In reply to Brigitte:

    Hello Diego,

    As I did not hear back from you, I expect the problem is solved and will close this thread. If you have further questions, add another post to reopen this thread or create another thread.

    Best regards,
    Brigitte

    For more information on buck-boost devices have a look at www.ti.com/buckboost

  • In reply to Brigitte:

    Hi Brigitte, sorry for the late answer, it was a trivia issue in the end, the board that drove this particular input had an other output pin connected to the driving pin, hence short circuiting to ground, making it appear as if it was the chip, sorry for wasting your time

    best

    Diego

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