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BQ24392: Identifying the charge current capability of a standard downstream device

Part Number: BQ24392

Hi Team,

How does BQ24392 know if the charge current capability of a standard downstream device is 100 mA or 500mA?

In the datasheet, only 100 mA is shown.

Thanks!

Roy Hsu

  • Roy,

    BQ24392 only indicates to the host the type of charger via the GPIOs. In a Standard Downstream Port, BQ24392 does not determine the charge current capability of the downstream device. The USB host determines this through enumeration of the device. BQ24392 does help the USB host determine the if high or low current should be used through the CHG_AL_N and CHG_DET pins, described in section 8.1.1.1 in the datasheet. If SW_OPEN is high-Z then the DP and DM switch is open and host to device communication cannot happen, thus the lowest charging current should be used (100 mA).