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BQ25798: BQ25798 with ON/OFF mechanical toggle switch

Rafael Gerges
Prodigy 50 points
Part Number: BQ25798


We are implementing the BQ25798 in a power-management solution and would like to add a mechanical ON/OFF toggle switch to fully turn the system on or off. However, after reviewing the datasheet and available application notes, we could not find any guidance on how to implement a complete system power-enable or shutdown using this device, since the BQ25798 does not provide a dedicated EN pin or an explicit method for disconnecting the system load. We would like to know whether Texas Instruments could provide recommended guidelines for implementing this feature, whether through the QON pin, SYS/BAT control, the use of external FETs, or any other TI-validated approach, while ensuring safe operation within the specifications of the BQ25798. 

 

Thanks in advance

Best regards

  • +1
    TI__Guru**** 170196 points

    Hi Rafael,

    The easiest way to fully turn off the system is to disconnect SYS load from the system load use a PFET with source connected at SYS pin and drain at system load.  The PFET needs a pull up resistor from gate to SYS pin.  Then the mechanical switch can connect gate to ground to turn on the PFET and float the gate, which will pull up to the SYS voltage and turn off the PFET.  

    Regards,

    Jeff

  • 0
    Prodigy 50 points

    Hello Jeff

    Thanks for you fast and precise reply. This solution is great for my application.

    Best regards.