• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 62 subscribers
  • Views 244 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.

BQ25155EVM: Behavior when VBAT < VBATUVLO

Riccardo Gaiati
Prodigy 60 points
Part Number: BQ25155EVM
Other Parts Discussed in Thread: BQ25155

Hi,

Condition: device in Low power Mode, VIN < VUVLO, VBAT > VBATUVLO so the battery discharge FET is turned on connecting PMID to the battery.

Event: VBAT < VBATUVLO

  • After the event the system powered via PMID turns off. Correct ?
  • What happens in this situation to device BQ25155 itself ?

According to what reported in the chapter 10 Power Supply Recommendations of the document bq25155.pdf, 

The battery voltage must be higher than 2.4 V or VBATUVLO to ensure proper operation [of the BQ25155]

  • What happens when VBATUVLO is set to 2.4 V ?

But in the description of the BUVLO Register (Address = 0x16) it is reported:

  • What happens when VBATUVLO is set to 2.2 V ? According to what reported above, the device needs at least 2.4 Volts.

Thanks in advance for your kind support.

Riccardo Gaiati

  • 0
    TI__Expert 4205 points

    Hi Riccardo, 

    Yes, on that condition when VBAT > VBATUVLO and VIN < VUVLO and after the event when VBAT < VBATULO the PMID will turn off. In this case the BQ25155 will shutdown. Yes, we recommend the battery voltage to be higher than 2.4V or VBATUVLO. In the case where VBATUVLO is set to 2.4V is recommended to operate with a battery above that threshold. If the VBATUVLO is set to 2.2V, we recommend being higher than 2.2V. So, 2.4V or VBATUVLO, whatever is lower. The device will still be functional above the BATUVLO threshold. 

    Regards, 

    Arelis G. Guerrero 

  • 0 in reply to Arelis Guerrero
    Prodigy 60 points

    Hi Arelis,

    thank so much for the prompt and clear reply.

    One last question: when the battery voltage goes below VBATUVLO  and the BQ25155 turns off, all the I2C registers gets their default values. Let's supposed that the device is attached to a charger (so VIN > VUVLO). According to what i understand reading the following paragraph, it shall not enter in Ship Mode. Is that correct ?

    Thanks again !

    Kind regards

    Riccardo

  • +1 in reply to Riccardo Gaiati
    TI__Expert 4205 points

    Hello Riccardo, 

    When the battery voltage goes below the VBATUVLO on this situation, the device will be off. On power up if is power on battery only without VIN the device will enter shipmode. You can exit ship mode by making VIN > VUVLO or by pressing the MR button for twake1. 

    Best regards, 

    Arelis G. Guerrero