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TPS65910A: Can RTC-Alarmtime-Int switch on a 9V to 5V DC-DC Switcher for 5V VBAT ?

Reinhold K.
Prodigy 70 points
Other Parts Discussed in Thread: AM3352

Hello,

I develop a battery-powered mobile system with a 9V Battery and a 3V Lithium Cell for the PMIC-RTC.
I use a 9V to 5V DC-DC Step-Down Converter with Enable Input for driving the PMIC.
I use TPS65910A31A1 with a AM3352.

The System has to start automatically at a programmed time.
When the System is off, the 9V to 5V DC-DC converter is switched off and the PMIC has no 5V on its inputs.

My question ist: If the programmed Alarmtime is there, can I use the PMIC-INT line to enable/start the 9V to 5V DC-DC Converter?
If the 5V is stable, the PMIC "sees" the 5V on its inputs and the AM3352 can then start?

Or is this scenario not possible?
Because I have more 5V driven hardware in this design, I have to switch off the 9V to 5V DC-DC Converter for "zero" power consumption in OFF state

Thank you for your help.
(I found no answer in the other threads for this question)

Regards

Reinhold

  • 0
    TI__Expert 6090 points

    Hi,

    this is possible to use the RTC alarm to wake up the PMIC, but very first time system has to be up before you can set this alarm and use after that for the second run. RTC alarm will generate and interrupt which can be used as a source for some secondary action.

    Main point is something need to set the alarm time.

     

     

  • 0 in reply to Puneet Sehgal
    Prodigy 70 points

    Hello,

    thank you for this answer.

    I see in the Datasheet, that the INT1 - Supplies is VDDIO (3V3) - which is normaly connected to VAUX33. But this power is not "ON", when the RTC-ALARM-INT1 is coming (See my first entry with the "Zero Power" Device). 

    So my question is: Can I use the INT1 - Line for Switch ON the 9V to 5V DCDC Switcher to Power the PMIC when the VDDIO is 0V? Did in this case INT1 powered from the Lithium Cell?

    If not, how can I resolve this Problem? Any Ideas?

    Thank you

    Reinhold