• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 627 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

BQ78350-R1: BQ78350 Shutdown Mode

Maciek Lewandowski
Prodigy 170 points
Part Number: BQ78350-R1
Other Parts Discussed in Thread: BQ78350

Hi,

We are using the bq78350 fuel gauge in a customers battery  which is sometimes stored for an extended period of time (few months). To maximize shelf life we wanted to understand if the low power SHUTDOWN Mode feature of the bq78350 is a viable option to use while the battery is sitting at the customers storage facility.

As I understand it, Shutdown mode can be entered in three possible ways: low voltage, time delay, or ManufacturerAccess command. The technical reference states that upon exit from shutdown mode, the gauge will undergo a full reset. Is that true under all three entry conditions? If so, will the reset cancel the learn cycle we perform just prior to shipping  to customer? Does the learn cycle have to be repeated in order for the fuel gauge to correctly track capacity, or would it be enough to simply perform a full charge?

Thank you,

Maciek Lewandowski

  • 0
    TI__Guru* 81034 points
    Hi Maciek,

    Shutdown (all 3 methods) does reset the coulomb counter, so the gauge will come out of Shutdown and use the voltage to estimate the State of Charge based on the ChemID. The gauge will still remember the Learned Full Charge Capacity from the learning cycle, but it will need to go through another cycle to make any new updates to the learned capacity to get the highest accuracy.

    If the CSYNC bit is set in data flash, this will synchronize the Remaining Capacity to the Full Charge capacity when full charge is reached. A qualified discharge will re-update the Learned Charge Capacity.

    Many users use Shutdown to minimize discharge in storage, although some users will do the learning cycle and avoid Shutdown to achieve the best accuracy at time-zero.

    I hope this helps,
    Matt