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BQ25798: Not working

Rafael Sidlo
Prodigy 10 points
Part Number: BQ25798

Tool/software:

Hello everyone,

I am currently working on a project with a 5V 5A UVS. However, I am experiencing some issues.

1. The battery is not functioning. It is charging, but it is not supplying any voltage.

2. The data sheet states that the output is PMID, but other sites state that it is SYS.

3. I attempted to program the IC, but I was unable to connect via D+/D-.

I link an Picture with my setup (I hope it's not confusing)

I would appreciate some assistance, as I am at a loss.

Thank you in advance.


  • 0
    TI__Guru**** 166626 points

    Hi,

    For 1, can you elaborate on how the battery is charging but not supplying voltage to SYS?  The internal battery FET between BAT and SYS turns on when charging so BAT and SYS should always be connected.

    For 2, In forward/charge mode, VBUS is connected to PMID through a MOSFET and SYS is the expected connection for the system load.  PMID can provide current to a load but that current counts against the total input current that the IINDPM loop regulates/clamps.  In OTG/reverse mode, the converter works in reverse to provide a regulated dc voltage at VBUS.  In backup/reverse mode = fast turn on OTG mode when VBUS drops below a set threshold, the regulated dc output is PMID.

    For 3, the charger's I2C registers can only be accessed using SDA/SCL lines.  D+/D- is only used at charger power up to determine a USB BC1.2 ports' output current capability.

    On the schematic, /CE should not be left floating but if the battery charge current is flowing, that pin is floating to GND.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Prodigy 10 points

    Hello
    thank you for you help. Let me correct some mistakes and I will text the results
    Thanks for now