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TPS65083x PWRBTN

Other Parts Discussed in Thread: TPS650830

Hi,

Some questions as below.

  1. Can EC_RST be driven low while PMIC enter emergency shutdown to reset EC?  Customer is considering long press PMIC PWRBTN to reset EC.  Any comment?
  2. Is there any way to disable PWRBTIN function?
  3. Is VRTC valid under emergency shitdown state?

Thanks!

Antony

  • Antony,

    1. The EC_RST will be driven low when the device enters emergency shutdown and delay for the EC_RST delay period.
    2. You can disable the emergency shutdown feature of the push button by writing all '0's to the PBCONFIG register bits 5:0. The push button will still be able to wake up the PMIC after an emergency shutdown.
    3. Yes
  • Hi Michael,

    Thanks for the reply. Some further questions for clarification.

    Regarding #1, does it mean EC_RST will be changed from high to low level after PMIC enters emrgency shutdown, and keep low for some period of time then back to high level? Is the period defined by TRST[1:0] bits in RSTCTRL register?

    #4. Does PCH_PWRBTNZ signal just follow the level of PWRBTNIN? Or anything else?
    #5 From above, it seems EC_ONOFFZ is the signal follow PWRBTININ??

    Thanks

    Antony

  • Antony,

    1. Yes,it is driven by the TRST length

    4. Yes, it is just a buffered output of PWRBTNIN for an input to PCH.

    5. Yes, EC_ONOFFZ is a buffered output of PWRBTNIN with a deglitch associated too. It meant to be used for the embedded controller, EC.

  • Hi Michael,

    1. What is the delay from PWRBTN to EN_ONOFF when the debounce time is 0ms and 30ms?
    2. Can we configure how long EC_ONOFF will stay low after PWRBTN is driven low?
    3. Considering the emergency shutdown feature of the push button is disabled by writing all '0's to the PBCONFIG register bits 5:0, i think EC_RST will not react after PWRBTN is long pressed low, right?
    4. What is SWDN bit used for? Can we use it to judge if emergency shutdown was triggered previously?

    THanks!

    Antony
  • Antony,

    1. It is the debounce time, either 0ms or 30ms. 30ms is default setting.
    2. EC_ONOFF will be low as long as the PUSH button is pressed. It is open drain so you can have an EC detect that it has been driven low then hold it low even after PWRBTN is released.
    3. Yes, the EC_RST reacts to the Emergency Shutdown not to the push button in either case. So if you turn on the push button assertion to Emergency Shutdown then, by indirect effect, you prevent the push button from affecting the EC_RST. 
    4. SDWN bit initiates a software shutdown command like the SHUTDOWN pin but, via software interface. You can use RESETZ pin to detect a shutdown and registers x08 and x09 to determine which type of shutdown caused it, (VR fault, thermal, push button or shutdown input like SHUTDOWNZ pin or SDWN bit.

    This is all in the datasheet please read the register section for more details.

  • Hi Michael,

    Thanks for your reply.   Some further questions as below.

    1. What is the die temperature threshold to trigger TEMP_ALERTZ?
    2. What are the conditions that we would drive RESETZ pin?
    3. Do we have any register that show us SHUTDOWNZ

    Thanks!

    Antony

  • Antony,

    1. Temp alert should be at when any of the on die temp monitors detect a HOT temperature. HOT is defined in the datasheet.
    2. In any SHUTDOWN event.
    3. You have the registers that I mentioned to you in the earlier post that will indicate a shutdown due to a fault. The other shutdown events (SHUTDOWNZ pin & SDWN bit) are controlled by the processor or EC typically so, there is no bit for them. Instead please use RESETZ that is a HW pin with the same functionality.

  • Hi Michael,

    I can't confirm which parameter is the HOT temperature threshold you mentioned.  I onl find THOT for each rail which is different among each rail.  Can you double confirm this?

    Besides, customer request a power off sequence.  I don't think we have it, right?  Should we just ask them to refer to "Figure 37. Sequence of Function Modes - Assuming the TPS650830 Application Configuration
    Connections"

    THanks!

    Antony

  • THOT is the HOT parameter. Once any of these indicators detect a HOT condition the TEMP_ALERTZ asserts LOW.

    I am separating out your sequence question to another thread as it is a different topic.
  • Hi Mike,

    From above you mentioned that PCH_PWRBTN is a buffer output of PWRBTNIN.  May I know if there's delay between them?

    Thanks!

    Antony

  • Its delayed by the debounce time specified in the datasheet. 0s or 32s selectable by I2C, 32s is set by default.
  • Hi,

    May I say EC_ONOFFZ and PCH_PWRBTNZ have exactly the same behavior?

    Thanks!

    Antony

  • Antony,

    Yes, EC_ONOFFZ and PCH_PWRBTNZ signals have same behaviour. The PWRBTNIN debounce delay can be configured in PBCONFIG register.

    Also, VRTC is on even in emergency shutdown.

    Thanks,

    Jay