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BQ25792: Can we enable and disable the OTG power functionaility

Basit Ali Khan
Intellectual 370 points
Part Number: BQ25792

Tool/software:

Hi,

I am designing a Type-C bi-directional power bank using BQ25792 chip. The functionality that is required is:

1- The Type-C port should charge the battery when a charger is connected at the required current configured over I2C at all times.

2- The Type-C port should supply back the power when a load is attached at the Type-C port but this functionality will not be always active and should be controlled through I2C as I am giving a tactile button to turn ON/OFF this functionality through microcontroller.

3- The BQ25792 does not have a fuel gauge so any fuel gauge for 1S battery that is recommeded with its BMS circuitry.

4- What is the charging current selection range of BQ25792? I mean, I am designing a universal type of circuit in which a battery from 250mA to 4000mA can be attached. What current range the MCU can convey?

5- When the BQ25792 is supplying current to the load can we control the output current to multiple ranges?

  • 0
    TI__Guru**** 165766 points

    Hi Basil,

    Regarding 1 and 4, the charger has charging enabled by default. The charger can be set from 100mA to 5A (default of 2A for 1S) using an I2C write to the ICHG register.

    Regarding 2, the host's GPIO connected to the tactile button can trigger an I2C write to the EN_OTG bit.

    Regarding 3, the host software could include a gauging algorithm that uses the charger's instantaneous ADC measurements.  Or, you can add a system side gauge.  I will forward to the gauge team for a recommendation.

    Regarding 5, in foward/charge mode, the charger's output current to SYS cannot be directly controlled/limited but can be indirectly limited by reducing the charger's input current limit (IINDPM) register. Note that while input current regulation, the battery will supplement the system load.  In reserve/OTG mode, the output current can be regulated using the IOTG register.  Note that the output voltage (VOTG) will fall if the current is being regulated.

    Regards,
    Jeff