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Original question:

BQ24298: STAT led blinking due to TS input

BQ24298: Battery not charging/no current being drawn by IC

Tayeb Wahidi
Prodigy 50 points
Part Number: BQ24298
Other Parts Discussed in Thread: BQSTUDIO, EV2400, BQ24296

Hi there,

I was having some difficulty with a power management circuit I am testing which uses the BQ2492RTWR chip.

When connecting the LiPo battery, there is no charging present and I can only assume that is because of the bigger problem, where there isn't any current being drawn from the circuit.

I have tried to go over every other posting on the TI forum website related to the chip in question in the hopes that the problem I am facing was either a common one, or at the least already mentioned. I don't think a similar issue has been posted, though it is possible that I may have overlook a different issues related to mine.

Original setup for the BQ24298

Original setup for BQ24298      <-- USB connector & Battery connector

 <--Changes were made on original setup to match the ref design.

Only difference is the resistor connected to ILIM--> 453 ohms instead of 317 & resistor parallel to thermistor is 30k instead of 31.23 K ( added thermistor to board).

After the changes the only differences are the 2 stated above. 

When I connect a micro usb cable (5.03v), Vsys is 4.16v. 

When I connected the 3.85 LiPo battery to J1E (our connector header for the battery). I measure no current at the header pins, even with an additional 50 ohm resistor (load)--> voltage across the pins matches the 3.85v of the battery itself.

I was wondering if you had any experience with this problem. Obviously the lack of battery charging is most likely linked to the lack of current being drawn. 

If there is any other information that I could provide to help in troubleshooting, please let me know. I will be working on the problem meantime regardless.

Thank you

Best regards,

Twahidi

  • 0
    TI__Mastermind 19195 points

    Hello Twahidi,

    Could you also share the device registers? During your attempts to initiate charging you can log the register with bqstudio, found here: https://www.ti.com/tool/BQSTUDIO

    Thanks,

    Nick

  • 0 in reply to Nick Brylski
    Prodigy 50 points

    Hi Nick,

    Thank you for your quick response. 

    I get these 2 messages  in the Battery management studio application.

    "Device ACK error"

    In the bottom left hand corner, I get the message in red: "Not able to find a free communications adapter"

    INPUTS: Vusb: 5.08V    VBat: 3.85V

    OUTPUTS:

    VBUS (pins 1 & 24): 5.08V          PSEL: 5.08V            PG:0.00V            STAT: 0.17V           SCL: 1.10V        SDA: 3.28V

    INT: 3.26V                           OTG: 3.28V                       CE:                     ILM:                  TS: 3.26V                 QON: 3.26V   

    BAT (pins 13 & 14): 4.16V           SYS (pins 15 & 16): 4.16V           PGND (pins 17 & 18): 0V

    SW (pins 19 & 20): 4.16V            BTST: 8.39V              REGN: 5.04V        PMID: 5.08V   VBUS (pin 24): 5.08V

    Thank you,

    Twahidi

  • 0 in reply to Tayeb Wahidi
    Prodigy 50 points

    CE and ILM are both 0V

  • 0 in reply to Tayeb Wahidi
    TI__Mastermind 19195 points

    Hi Tayeb,

    Do you also get the same issue with the online GUI?: www.ti.com/tool/TI-CHARGER-GUI

    Is the EV2400 working OK with the charger EVM?

    Thanks,

    Nick

  • 0 in reply to Nick Brylski
    Prodigy 50 points

    Yes, though in the list of available device, the 24298 is not listed, the 24296 however is. I realize they are very similar so I am not sure if that is related to the GUI connectivity issues.

  • 0 in reply to Tayeb Wahidi
    TI__Mastermind 19195 points

    Hi Tayeb,

    BQ24298 is only supported by BQStudio at the moment.  With BQ24296 you can use the online charger GUI or the software found on the product page here: www.ti.com/.../sluc495

    Just to confirm, you had existing design with BQ24298 working OK. Now you are seeing the charging issue after replacing U2B with BQ24296-- so no other changes besides U2B?

    How many units are showing the issue? How many battery packs?

    Thanks,

    Nick

  • 0 in reply to Nick Brylski
    Prodigy 50 points

    We are using the BQ24298, assuming the problem can't be solved-there was a thought to try and replace the 24298 with the 24296 (haven't fully research if it'll be compatible).

    The BQ24298 is getting power (from the USB), but the charging issue is present and as mentioned above, there is a problem connecting to the BQStudio.

    I have tried to compare the 24298 Eval schematic with the datasheet schematic to the circuit and made a few changes to mimic the eval board setup but still no luck connecting to the chip.

    We might purchase the Eval board for the 24298-and worst case scenario would be using the Eval board instead of our 24298 circuit-but the ideal plan is to get our PCB to work, as the other circuits on the board, all of which are important, have been verified already.

  • 0 in reply to Tayeb Wahidi
    TI__Mastermind 19195 points

    Hello Tayeb,

    I would suggest isolating the following circuit from the charger and then try. It may not be working as intended.

    Nick

  • 0 in reply to Nick Brylski
    Prodigy 50 points

    Hi Nick,

    Sorry for the delayed response, I was working on something else at the same time. I was actually able to get the IC to charge the battery by shorting J1F ( in the schematic above), I had done it earlier on the first board I was testing but that one started to overheat-so I didn't try it on the second board.

    I am currently trying to get the IC to now communicate with the Battery studio application.

    I was wondering a few things:

    -If the device is not automatically detected does this indicate a major issue,or does 'forcing' the IC connect still work.

    -When I select the desired IC, a warning comes up in red at the bottom of the screen "No free adapters are available for use on this system"-->does this indicate an issue with the IC (schematic) or a missing driver on the PC.

    Thank you for all of your help

    Tayeb

  • 0 in reply to Tayeb Wahidi
    TI__Mastermind 19195 points

    Hi Tayeb,

    Are you using an ev2400 to connect to bqstudio? Do you have any other charger EVM's you can try communicating with? 

    BQstudio would not automatically detect the charger if the matching .bqz is not found. Which version of bqstudio are you using? Also what are the top marking of the IC?

    Can you share waveforms of VBUS, SW, SYS, BAT when connecting USB power? You may also want to look at the SDA/SCL lines when connecting EV2400.

    Thanks,

    Nick