• State
  • Replies 7 replies
  • Subscribers 63 subscribers
  • Views 73 views
  • Users 0 members are here
Support feedback
Options
Options
Related

BQ25190: buck-boost rail GND short issue

Gilhwan Cha
Prodigy 60 points
Part Number: BQ25190

Tool/software:

Hi, this is Gilhwan Cha.

A buck-boost rail grounding and short-circuit issue occurred.

It was in use on a custom board, and the decap configuration utilised the same decap as the EVK.

The problem arose when the Vsys pin and BUBO pin were shorted.
Naturally, this short should not occur, but it happened accidentally for about one second.
Subsequently, when power is applied, heat is generated from the BQ25190.
Furthermore, the BBSW1 and BBSW2 pins are shorted to GND.
Additionally, when the 5V supply is applied, IN is detected as 4.75V.

Thanks.

  • 0
    TI__Mastermind 18005 points

    Hi,

    It appears that this test may have resulted in device damage. Can you check how much current is being pulled from the 5V input supply? How much quiescent current does the battery pin pull now, and is I2C still responding?

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 60 points

    The I2C is being powered up using the 3.3V voltage from the BUCK rail, but it does not function(I2C) when the power is switched on. After some time has elapsed, however, the I2C operates normally upon MCU reset. (It appears that MCU initialisation does not occur simultaneously with boot-up.)
    After pressing for 10 seconds, it is confirmed that the HW is reset.

    We'll measure the current and more detailed ones as we have time.

    Thanks.

  • 0 in reply to Gilhwan Cha
    TI__Mastermind 18005 points

    The I2C working on MCU reset seems to suggest the I2C issue is not necessarily with the BQ25190. However, based on a shorted BBSW1 and BBSW2 it does still seem to indicate some damage in the Buck-Boost section of the device. Is there any evidence of solder issues that may indicate why BBSW1/2 are shorted to GND? Looking forward to current and detailed measurements. I will try a similar test on my bench to see if I'm able to recreate the behavior you are able to share.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 60 points

    I just did a quick test: 0.34A is being drawn from the 5V input with no load.
    After replacing the MCU, I2C is running smoothly (I guess the MCU was also damaged).
    When using only the battery (3.7V), the Vbat -> Vsys line seems to pass well, in which case it uses 0.26A.

    For BBSW1/2, a short test with a multimeter shows that it has the same potential as GND.

    Thanks.

  • 0 in reply to Gilhwan Cha
    TI__Mastermind 18005 points

    Hi,

    This does seem to indicate there is still some damage present. With no load the quiescent does seem too high. I won't be able to run the test until Monday but I'll see if the same test produces similar results on an EVM.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 60 points

    Have you tested this ? We'd love to know if you have similar results.

    Thanks.

  • 0 in reply to Gilhwan Cha
    TI__Mastermind 18005 points

    Hi Gilhwan,

    I haven't been able to recreate the results you listed, but I still have a bit more testing to do to confirm this.

    Best Regards,

    Juan Ospina