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BQ24070 shutdown output power

pascalfifre
Prodigy 40 points
Other Parts Discussed in Thread: BQ24070

Hi All,

I use actually a BQ24070 to charge a battery and power an embedded  linux system. It works fine.

But I need to halt the system by the OS.

I've seen that when the system works on battery, I can't disable the output power. When I put the CE pin to low the system stay alive.

Is it possible to turn off the output power?

Thanks a lot

 

  • 0
    TI__Mastermind 36110 points

    The bq24070 datasheet paragraph "Sleep and Standby Modes" helps desscribe the functionality you see.  With power applied to IN and CE pulled low, the bq24070 enters the low-power standby mode where the power FET, Q1 is turned off but the charge FET, Q2, is turned on to power the system from the battery.  The bq24070 is not designed to allow the user to disconnect the battery from the system.

  • 0 in reply to Matthew Day
    TI__Mastermind 32370 points

    Hi Pascal,

     

    In addition to Michael’s comment above, the CE (chip enable) digital input is used to disable or enable the IC. A high-level signal on this pin enables the chip, and a low-level signal disables the device and initiates the standby mode. In this mode, internal power FET Q1 (see block diagram on Figure 5 in the datasheet on page 12) is turned off; the battery (BAT pin) is used to power the system via Q2 and the OUT pin.

     

    If you want to control the system, I would recommend the bp24075/79 that has a SYSOFF pin to control the system output.

     

     

    I hope that helps!

     

     

    Thanks

    Tahar