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BQ25790: BQ25790 QON pin default status

Hollis Liu
Intellectual 2535 points
Part Number: BQ25790

HI team,

i would like to check the default status of QON pin after POR. It is default 3.2V or 0V? 

if it should be 3.2V after POR, what kind of issue will result in the QON is pulled 0 after POR? Thanks. 

  • 0
    TI__Guru*** 143980 points

    Hi Hollis,

    /QON is ~3.2V after power (approx 2 diode drops below REGN). If pulled low, /QON behaves as explained in the datasheet:

    Ship FET Enable or System Power Reset Control Input – When the device is in ship mode or in the shutdown mode, the SDRV turns off the external ship FET to minimize the battery leakage current. A logic low on this pin with tSM_EXIT duration turns on ship FET to force the device to exit the ship mode. A logic low on this pin with tRST duration resets system power by turning off the ship FET for tRST_SFET (also setting the charger in HIZ mode when VBUS is high) and then turning on ship FET (also disabling the charger HIZ mode) to provide full system power reset. During tRST_SFET when the ship FET is off, the charger applies a 30mA discharging current on SYS to discharge system voltage. 

    Regards,

    Jeff