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BQ25890H: several questions for QC3.0 charger

TS Yang
Genius 4800 points
Part Number: BQ25890H

Hello,

I found posting of below link and am looking to expand on it. (all threads are locked so I'm writing a new one.)

https://e2e.ti.com/support/power_management/battery_management/f/179/t/558876

Here are my questions,

1. If the host is off, let us know how the quick charge mode works. I can not find it in the datasheet.

2. The products we are developing are very sensitive to temperature.
So if the host gives a different signal depending on the temperature, please let me know how to distinguish between fast charge, normal charge and charge stop.

3. If we are using a fuel gauge, is there a way for the charger to read its output directly?

4. The Simplified Schematic at the bottom right of the datasheet 1 page does not clearly show how the I2C bus and host control are specifically divided.

Please explain more details.

thanks,

TS

  • 0
    TI__Guru**** 166896 points
    Hi TS,

    Regarding 1, for high voltage (HV) adapter protocols requiring D+/D- voltage level shifting, a host is required.

    Regarding 2, fast/max/quick charge are marketing terms used to distinguish between chargers that can charge from high voltage adapters with lower current, and therefore related input voltage droops, compared to those occurring at 5-V, like legacy USB port, at the same power level. There is no other difference between "fast" charging and normal charging if normal charging is set to the highest charge rate for the battery and the charger is not being input power or voltage limited. The bq2589x family reports VBUS status (HV adapter or not) and charge status in I2C REG0B. Also the STAT pin changes state when charging and not charging.

    Regarding 3, the charger does not have a processor and can only interact with other devices, like a gauge, with either I/O pins from those devices or via I2C. A host processor is typically needed to be the I2C master and intermediary between the charger and gauge.

    Regarding 4, the charger has default settings to allow charge. Both the 890H has D+/D- that will attempt to automatically detect the type of adapter and set the charger's input current limit to match that adapter. A host and host software are needed to change any of the charger's default settings (input current limit, battery charge current, battery regulation voltage, etc).
  • 0 in reply to Jeff F
    Genius 4800 points

    Hi Jeff,

    thanks for your kind answer.

    I am a beginner to charger, but I have a meeting with a client based on your answer and I would like to confirm the following to you.
    (There are several questions in the middle, and the parts are marked in red.)

    1. QC3.0 support
    -. OK

    2. Charging method when DUT power is off.
    -. QC3.0 support is not available. Operates in normal 5V charging mode
    Question > Is charging proceeding according to ILIM setting value? Or is it charged in OTG Mode?

    3. Whether below charge scenario is operating at high temperature
    -. scenario ppt file : charge_Control_SW_scenario.pptx
    -. Can this scenario be controlled by I2C interface?

    4. OVP function Built-in
    -. OK
    -. OTG Mode th : 6V
    -. QC 30. Mode th : 104%@VIN

    5. If only battery gauge read is possible, is there any problem in using QC3.0?
    -. The IC used in client is MAXIM MAX17058.
    -. Battery Gauge IC <-> HOST Chip <-> Charger
    Question > How to configure the block diagram between ICs?

    6. How else should I configure it for use guage output?

    Any advice is welcome.
    thanks,
    TS
  • 0 in reply to TS Yang
    TI__Guru**** 166896 points

    TS,

    Regarding 2, without host support for high voltage adapter and I2C communication with the charger, the charger will charge from 5V VBUS in default (standalone) mode with ICHRG=2.048A, VBATREG=4.2V and input current limited by the resistor on the ILIM pin.  To enter OTG mode once VBUS is removed, thereby providing 5V back to VBUS from the battery, the host will have to write the OTG bit to high because its default is low.

    Regarding 3, yes, with host software, you could, for example, use battery temperature from the gauge to determine when to change the charge current.

    Regarding 5, I not familiar with the MAXIM gauge.  A gauge is typically powered by and typically only monitors the battery voltage, current and temperature.  It is independent of the adapter.  The host is the I2C master with the charger and gauge being the I2C slaves, all on the same I2C bus.  Your software periodically reads from the gauge and then makes decisions about how to change the charger's I2C settings for charge current and termination.  Some gauge's can be configured as an I2C host and can communicate directly with the charger.

    Regarding 6, see response above.