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TPS659037: About OFF sequence time

Tsukui Yusuke
Guru 21930 points
Part Number: TPS659037

Hi,

In the current circuit, the time from the fall of PWRON to the fall of RESET_OUT was approximately 12 sec.
Could you tell me how to shorten the period until shutdown sequence?

I confirmed the following post.
e2e.ti.com/.../620511

”Another way is to connect GPIO_7/POWERHOLD and RESET_IN directly to LDOVRTC_OUT. This will enable the PMIC as soon as power is supplied, and will not require any software to keep it up.”
If this method is used, can I shorten the time until RESET_OUT fall?

Best Regards,
Yusuke
  • 0
    TI__Genius 17380 points
    Hi Yusuke-san,

    Thank you for searching the forum for previous answers, I'm glad to help you get to your desired goal.

    As noted in the previous post, POWERHOLD and RESET_IN can both be OFF requests, with the note that POWERHOLD is only an OFF request when DEV_ON bit is set to 0b. A list of all possible OFF Requests is in the datasheet Table 5-11. Generally it will depend on how they want to shutdown. If they want to use software, then setting DEV_ON or SW_RST may be enough. If they want to use hardware, POWERHOLD, RESET_IN, or PWRDOWN may be sufficient. It often depends also on the orderable as to which may be most effective.

    If you have more questions on the behaviors, please include the specific part number orderable as the different versions (one time programmable OTP settings) can behave differently. For example, RESET_IN polarity can be high or low.
  • 0 in reply to Kevin LaRosa
    Guru 21930 points

    Kevin-san,

    Thank you for your kind support.
    Customer is considering TPS6590378.

    Let me know one more thing.

    1.
    I would like to confirm just in case...
    Can I shorten the time until resetout falls by using the following method?
     "Connect GPIO_7/POWERHOLD and RESET_IN directly to LDOVRTC_OUT"

    2.
    Customer was using the PWERON pin only to perform ON sequence / OFF sequence.
     (Customer wants to turn on / off the sequence with hardware only.)
     "In the current circuit, the time from the fall of PWRON to the fall of RESET_OUT was approximately 12 sec."

    However, for the following connections,
    How should I generate an Off Request?

    6.2 ACT2OFF Sequences
    http://www.ti.com/lit/ug/sliu011f/sliu011f.pdf#page=16

    Could you tell me the recommended method.
    We are currently considering the following.
    ・Input the signal to PWERON and LDOVRTC_OUT to AND logic
    ・Input AND logic output to GPIO_7 / POWERHOLD and RESET_IN

    Best Regards,
    Yusuke

  • 0 in reply to Tsukui Yusuke
    TI__Genius 17380 points

    Hi Yusuke-san,

    TPS6590378 does have GPIO_7 configured as POWERHOLD per the User Guide (same as the one you linked): http://www.ti.com/lit/ug/sliu011f/sliu011f.pdf

    Connecting GPIO_7 / POWERHOLD and RESET_IN directly to LDOVRTC_OUT will have the effect described in the datasheet - it will cause an immediate ON request. This will not cause the system to shut down.

    To get a shutdown event, I would recommend using the POWERHOLD pin like a simple enable pin - when it is high the device will power on. When it goes low, it will power down as long as the DEV_ON bit is 0 and there are no active interrupts. Alternatively, RESET_IN could be used and then it would shut down regardless of DEV_ON or interrupts. If using POWERHOLD, RESET_IN should be connected to LDOVRTC_OUT unless you want to have two sources of disabling and if using RESET_IN, then POWERHOLD should be connected to LDOVRTC_OUT.

  • 0 in reply to Kevin LaRosa
    Guru 21930 points

    Kevin-san,

    Thank you for your response.
    Please let me ask one more question.

    1.Can "PWERHOLD control” be faster to RESET_OUT fall than ”PWRON control”?

    2.About DEV_ON control
       0 was written to the DEV_ON bit.
       However, the shutdown sequence is not started.
       Could you tell me how to enable DEV_ON bit control? 

    Best Regards,
    Yusuke

  • 0 in reply to Tsukui Yusuke
    TI__Genius 17380 points

    Hi Yusuke-san,

    1. Yes, RESET_OUT should go low almost immediately after POWERHOLD falling edge as long as no other ON requests are active. PWRON shutdown requires a long key press 

    2. Starting at Table 5-9 in the datasheet explains the ON and OFF requests and what can gate them. For example: "The DEV_ON event has a lower priority over other ON events; it forces the TPS659037 device to go to the OFF state only if no other ON conditions are keeping the device active"