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BQ24295: Charging status indicator still in 'in progress' status

Nicolas Chanut
Prodigy 70 points
Part Number: BQ24295

Hi

 

Could you help

 

I have a problem with the "Charging Status Indicator".

My manipulation is the following :

The board is  configured with USB, the battery is connected ( OTG is disabled, Charging is enabled).

I connect the external power supply.

I disconnect the external power supply.

A this moment the bit for the detection stayed at "1" (0xAC, bit 3).

PMID is at 4V and the USB is at 4V.

If I disabled and enabled the charging, everything goes well. But if I connect and disconnect the external power supply I find again the problem.

I don't know if this issue could come from the capacitor used on power supply.

Thanks for your support.

 

  • 0
    TI__Mastermind 25800 points
    Hey Nicolas,

    I am having some difficulty understanding what you are seeing.

    You are seeing two different conditions, if you connect and disconnect a power supply one event occurs. And if you toggle the charge enable bit, another event occurs?

    One question I had was which bit of which register you were referring to? You mentioned bit 3, which there only two involving a status: BAT_OVP and DPM_STAT. Do you mean the CHRG_FAULT bits of Register 09? Please clarify.

    Some other questions: What is your battery voltage? Are you seeing a voltage at Vsys? Do you have a snapshot of the switching waveform when you connect your external supply?


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 70 points
    Hello,

    I start my system with external power supply connected and battery connected (LiIon 4.2V near fully charged)
    The system reset the BQ24295 and configure all registers

    I read theses data for all registers (from 0x00 to 0x0A) after my setup
    5F 1D 01 00 AA 9C 03 00 A4 00 C0

    Reg 0x08 has a value of 0xA4 so :
    Adapter port detected
    Fast charging
    No DPM
    Power Good
    Not in thermal regulation
    Not in VSYS Min regulation

    Note also that Reg 0x01 have a value of 0x1D
    OTG disable
    Charge enable

    Now I remove external power
    I've got this status :
    5F 1D 01 00 AA 9C 03 00 AC 00 C0

    Reg 0x08 has a value of 0xAC so :
    Adapter port detected
    Fast charging
    DPM in progress
    Power Good
    Not in thermal regulation
    Not in VSYS Min regulation

    Note also that Reg 0x01 remains in 0x1D state (OTG Disable)
    I have 4.29V on USB port, (does it come from OTG power supply - that is disabled in register ?)
    And I got stuck in this state ! DPM never end.

    The only workaround I found is when I detect that DPM is on for too long time, I disable battery charging (Bit4 of REG01) and reenable it 10ms after.
    It seems that OTG and Battery Charging have some coupling (that make sense, as we won't charge battery in OTG mode)
    Default: OTG Enable (1) Note: OTG_CONFIG would over-ride Charge Enable Function in CHG_CONFIG

    After this, DPM stop and restart. But I would need some confirmation on all theses aspects, as I can't be sure it will be reliable ...
  • 0 in reply to Nicolas Chanut
    TI__Mastermind 25800 points
    Hey Nicolas,

    Could you try disabling the battery FET (Q4) via REG07[5] = 1?

    This would disconnect the battery from the system and we could then investigate whether some extra power is holding up VBUS even when you disconnect power.

    Another check would be to add a heavy load to the VSYS pin to see if the part stops switching.


    Regards,
    Joel H