• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 129 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

BQ25708: REGN drops out periodically

BQ25708: Follow-up to "REGN Drops out Periodically"

Andre Cilia
Prodigy 205 points
Part Number: BQ25708

Hi,

This is a followup to the thread which was started here:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1116326/bq25708-regn-drops-out-periodically

In that thread I described an issue whereby random IC's would seemingly reboot periodically, with the voltage on REGN oscillating between the required 6V and 0V and the charger chip repeatedly rebooting.

The suggested modifications were applied and still however this issue remains.

What else can be tacked?

Thanks and regards

Andre Cilia

  • 0
    TI__Expert 4780 points

    Hi Andre,

    I recall your last post and we suspected a short across one of the FETs could be causing issues, due to manual rework. With the new board, are you certain there are no shorts across inductor or FETs?

    Thinking more about how to debug and narrow down the issue, I have a couple questions and suggestions:

    - What is the current limit / clamp set to on your power supply?

    - Have you tried to power up from Battery only? By default the chip will power up in Low Power mode, but you can set EN_LWPWR to 0 (0x12[15]=0) to enable Performance Mode which will start up REGN.

    - Powering up from VBUS, you can try to set ILIM_HIZ to 0V to force HIZ mode (converter will be disabled) to see if the REGN LDO stays low in HIZ mode as well.

    Thanks,

    Khalid

  • 0 in reply to Khalid Bairuti
    Prodigy 205 points

    Hi Khalid,

    Nice speaking to you again!

    I can confirm that I am finding a dead short across the FET driven by pin LODRV1.

    Unfortunately any configuration that I set to the rebooting IC is immediately lost upon reboot thus I annot perform the test you propose.

    Best regards,

    Andre

  • 0 in reply to Andre Cilia
    TI__Expert 4780 points

    Hi Andre,

    If you are seeing a dead short across the Low Side Buck FET then the other tests are irrelevant. My  suspicion would be a manufacturing or layout issue. The FETs you should be fine as they have been used on a lot of buck-boost controller designs..

    Thanks,
    Khalid

  • 0 in reply to Khalid Bairuti
    TI__Expert 4780 points

    Andre,

    Any update on this issue?

    Khalid