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TPS65219: TPS65219

Part Number: TPS65219
Other Parts Discussed in Thread: TPS22965,

We are using the PMIC TPS6521902 in our design for powering up AM625x. We require clarification regarding the below queries,

1,We understand that EN/PB/VSENSE is default set to PB in case of TPS6521902.As per datasheet its not recommended to change this setting through I2C.So we want to understand the functionality of this PB pin. Other than to perform a cold reset , what are the other scenarios during which Push button requires to be pressed? TI in one of the calls mentioned that PB needs to be pressed to bring the PMIC from Low power state to Active state. Is this in addition to the ON/OFF I2C request which can be made through software control? Also is a manual intervention required every time to wake up the PMIC by pressing Push button? We require your immediate feedback on this as this is very critical to our design as the application is for a fire panel safety system where manual intervention is not a feasible option to maintain the system active.

2,If  the PMIC TPS6521902 is accidentally given +5V input instead of +3.3V (i.e if Vsys= 5V), what would be the implications? Is there a way by which the TPS6521902 is programmed to detect this and accordingly enable or disable the power switch TPS22965? else 5V would be fed to AM62xx on the pins which require 3.3V.

3,Its  mentioned in datasheet that RESET pin of PMIC can be configured for both WARM and COLD reset. What is the default configuration and is COLD reset applicable to 02 variant?

4,What is the significant difference between Active and Standby state? Whether any output rails are disabled? 

  • Hi,

    Thanks for reaching out! Below are the responses to the questions in the previous message. Please let us know if additional information is needed.

    1. Yes; The "EN/PB/VSENSE" pin on TPS6521902 is configured as PB. Here is how it works:  
      • The PB pin can be used to wake-up the PMIC if it goes to Initialize State (where all the rails are disable) after the first power-up. Please note, an OFF request can be sent through I2C to send the PMIC to the Initialize state but but an ON request can't be sent through I2C so the PB pin will be needed to wake up the PMIC and sent it back t Waking up the PMIC with the PB pin will require pulling it low (below the VIL-threshold) for the configured tPB_ON (around 600ms. See datasheet for accurate parameter spec). The other option to get the PMIC into the ACTIVE state would be using the EN pin of the pre-regulator to execute a power-cycle and power the PMIC again from "No Power" to "Active". 
      • Please note this PMIC (TPS6521902 specifically) comes with the FSD feature enable by default. This means the state of the PB pin will be ignored during the first power-up. Once the PMIC arrives to the Active state, then it will start monitoring the state of the PB pin. 
      • The power-down sequence can be triggered from the Active state by pulling the PB pin low for tPB_OFF-time (around 8s. See datasheet for accurate parameter spec). Just for your reference, the power-down sequence can also be executed through I2C (I2C-command to I2C_OFF_REQ in MFP_CTRL register). Executing a power-down sequence (either by using the PB pin or through I2C) is recommended to make sure the PMIC turns OFF the rails in sequence before the pre-regulator goes below the VSYS UVLO. 
      • A fault recovery on the PMIC or a cold reset will not require the use of the PB pin to wake-up the device as it will automatically go back to the Active state. 
    2. The OVP of the input supply on the PMIC is not configurable. This means the PMIC will execute the power-up sequence with a 3.3V or 5V input supply. An external OVP supervisor combined with a switch could be used to disconnect the supply from the PMIC if it goes above 3.3V. Just for reference, here is the link to the product page of the TI suppervisors: https://www.ti.com/power-management/supervisor-reset-ic/products.html
    3. The TPS6521902 variant was configured to have all PMIC rails (Buck1/2/3, LDO1/2/3/4 and GPO2) enabled by default on both states; Active and Standby.

    Thanks,

    Brenda