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BQ24163 - Output disable

Melissa Campillo
Prodigy 40 points
Other Parts Discussed in Thread: BQ24163, BQ24075

It appears that on BQ24163 I can not disable the SW pin output. Is there a way to do this? And if not, is there a different TI part that will allow me to disable the output ? It appears that I can put the charger in HIGH-Z mode but not disable the output.

  • 0
    TI__Genius 11680 points

    Melissa,

    Could you see if you can get the following questions answered?

    1) When he says the "SW pin" does he mean the SYS output voltage rail?

    2) Is Vin connected? If so, what is the value?

    3) Is the battery connected?

    4) Is he expecting to have an Enable pin or I2C bit like one of our DC/DC converters so he can shut off the SYS rail, and therefore his system even when power is connected?

    Thanks!

  • 0 in reply to Nate
    TI__Guru*** 146725 points

    When Vin is applied, the SYS rail is always on.  When only the BAT is attached, the SYS rail is powered from the battery.  That is how most of our chargers operate.  It is not like a dc/dc converter with EN pin.  The assumption is that you want/need SYS whenever there is something to power it.  I know of one linear charger, bq24075, that has a pin that can disable the SYS rail.  One option would be to place a FET in series with the input pin to the charger in order to isolate it from the input power source.  If necessary you could the same thing with the battery.   Just curious as to the reason for doing this?

  • 0 in reply to Nate
    Prodigy 40 points

    1)Yes

    2)If vin is connected I do not need to turn the sys off and it will be +5v if connected.

    I want to turn the unit off (SYS off) under software control so my load will not drain the battery if I do not have Vin or USB power.

    3)yes

    4)yes This is what I want when Battery is plugged in so battery will not drain, but if Vin is connected I do not care.

  • 0 in reply to Melissa Campillo
    TI__Guru*** 146725 points

    So, he wants to power the system from battery only at certain times, not all the time, yes?  If so, then the only way I see to do that with this part is to place a FET in series with the battery that he can disconnect and connect the battery as he chooses.