Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 65 subscribers
  • Views 248 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:

BQ25798EVM: PCB copy doesn't charge and can't be programmed with USB2ANY

BQ25798EVM: The charger has been configured with USB2ANY, but why doesn't it charge?

Foca Andrei
Prodigy 100 points
Part Number: BQ25798EVM
Other Parts Discussed in Thread: BQ25798

Tool/software:

Hello! I decided to make a new post from the previous thread as we can now successfully communicate with the BQ25798! Just one more problem, it doesn't seem to charge the battery. I have a multimeter connected in series with the battery, and I also have my 5V-3A PSU connected at the input. I know 1 LED draws about 1mA, the chip draws 5ma, and we have 2 LEDs (see the schematic, 1 for STAT and another for 3V3 indication), so 7mA total draw, which is the case! In the GUI it says "Trickle charge" right now, but it doesn't appear to draw ANY current from the PSU, maybe at max 1mA! 

Also the STATUS LED now lights up every time I put the CE SHUNT as said in the BQ25798 EVM datasheet, because my board is pretty much a copy of it.

The charger may be seeing my Sodium-Ion battery that I want to charge as dead... Because its voltage range is between 3.95V and 1.5V, now it's at about 2.16. For a Li-Ion that battery would be long dead but this is not the case for us and I suspect it doesn't trigger normal 0.5A charge because of that. So how can I tell it to straight up forget trickle && pre-charge and go to normal charge? What are the settings I should enable/disable? See all the GUI stats and settings bellow:

   

And the GUI images:
            

  • 0
    TI__Mastermind 20220 points

    Hi Foca,

    Thanks for posting. We are currently in US holiday weekend. A team member will look into this and reply by mid next week. Thanks for your understanding.

  • 0 in reply to Jing Zou
    Prodigy 100 points

    Ok, I will wait for your response then.

  • +1 in reply to Foca Andrei
    TI__Intellectual 1110 points

    Hi Foca,

    Trickle charge can't be disabled but precharge can be effectively disabled by setting VBAT_LOV to 15% of VREG.

    From the schematics:

    1) Ensure VACx is connected to VBUS if no ACDRVx is used.

    2) Ensure ACDRVx is connected to GND if there are no MUX FETs.

    3) Ensure SDRV capacitor is connected to GND and not BAT if no shipFET is used.

    4) Ensure BATP is connected to NFET source if ShipFET installed, otherwise it connects to BAT

    Regards,

    Jared Baxter

  • 0 in reply to Jared Baxter
    Prodigy 100 points

    Update: I removed the ShipFET (bypassed it through the jumper) and followed the above steps and it charges.

    BUT I noticed my battery gets completely drained if I leave it connected to the system without anything on VBUS. That must be the reason why the ShipFET must be present? To prevent battery current leakage to the system?

  • 0 in reply to Foca Andrei
    TI__Intellectual 1110 points

    Hi Foca,

    Correct, the ShipFET does allow the charger to enter into shutdown or ship mode to reduce Iq. From your schematic, if J14 is installed, the 3.3 V Global circuit is likely the greater cause of the battery drain.

    Regards,

    Jared Baxter