• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 560 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.

BQ25121: Switching from Trickle Charge to Normal Charge mode

Maarten Witteveen
Prodigy 60 points
Part Number: BQ25121
Other Parts Discussed in Thread: , BQ25120, BQ25120A

We are using the BQ25121 in our current production version. 
We have found the following repeatable issue with this part.

When the battery has been depleted to the point where it will no longer switch on (below 3.3V) the IC will start charging in trickle mode.
To our understanding the IC should switch at ~3.0V to normal charging. I have measured repeatadly that a battery at >3.2V is still charged in trickle mode.
The only way to switch to normal charging is to reset the charge cycle by unplugging the device from the charger. This sometimes also takes an additional restart for it to register correctly.

On a 100 pieces test the result is around 50% of the modules that transition smoothly from trickle to normal charge, the others need 1 or multiple resets.

Is this a known issue? Or what should be checked to solve this issue?
To our embedded engineers understanding this is handled inside the IC and our own firmware does not impact this transition, is this correct?

  • 0
    TI__Genius 12485 points

    Maarten,

    I would recommend that you move to the BQ25121A which is the new version of the BQ25121. We are planning to release in May and we have samples I could provide you. 

    The IC will switch from precharge to fast charge at 150mV above the 3V setting. I will clarify the datasheet to describe this. 

    You also need to make sure that the BUVLO registers are not written in the Firmware. Leave the IC's 0x09 register to default to not impact this settings. 

    regards,

    gautham

  • 0 in reply to Gautham
    Prodigy 60 points

    Hi Gautham,

    Thanks for your reply, that does sound like something that would fix our current issue.

    I would like to request 5-10 samples to be send to:

    REMOVED PRIVATE INFORMATION BY MODERATOR

    Kind regards,
    Maarten

  • 0 in reply to Maarten Witteveen
    Prodigy 60 points
    One more question for our PCB designer.
    Is it a drop-in replacement or will it have any updates to the pin-outs and connections?
  • 0 in reply to Maarten Witteveen
    Prodigy 60 points
    And we are currently using the 2.5 Volt default version of the BQ25120, will that also be available with this A version?
    On the website I can only find the 1.8V of the BQ25120A.
  • 0 in reply to Maarten Witteveen
    TI__Genius 12485 points
    Maarten,

    I have edited your post to remove your personal information. Last thing i want is for you to be spammed by some search engine :)

    I will contact you offline on the samples.

    To answer your other question- it is a 2.5V version with watchdog timer disabled, drop in replacement, pin2pin, bom2bom and software compatible with BQ25120A.


    regards,
    gautham