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TPS68470 LED replacement

Satoshi Yone
Expert 3600 points
Other Parts Discussed in Thread: TPS68470

Hi, 

 

Could you check the attached ppt file? The customer would like to take measures this situation. Could you advice me for this?

 

TPS68470.pptx

Best Regards,

Satoshi Yone

  • 0
    TI__Genius 16870 points

    Satoshi-san,

    They should follow this post for connections if the LEDs are not to be used.

  • 0 in reply to Michael Green
    TI__Expert 3600 points
    Hi, Michael,

    Thank you for the reply. The post is the same business. I understand they should follow the setting, but there is a possibility that the ppt situation will happen. Could you give me the advice?

    Best Regards,
    Satoshi Yone
  • 0 in reply to Satoshi Yone
    TI__Genius 16870 points

    Maybe they can use jumpers to switch between the 2 settings but, the requirements don't change from the recommended connections if not using LEDs. e2e.ti.com/.../502689

    Otherwise, don't use LEDs on a board that is intended to not have the the LEDs.

  • 0 in reply to Michael Green
    TI__Expert 3600 points
    Hi, Michael,

    Thank you for the answer. I have to discuss more...

    "A TPS68470" design for connecting with LED
    "B TPS68470" design for connecting with non-LED e2e.ti.com/.../502689

    - Dose the "A TPS68470" flow current to non-LED circuit? (They concern that the IC is broken.)
    - When the "B TPS68470" connects to LED, the IC flows current to LED?

    Best Regards,
    Satoshi Yone
  • 0 in reply to Satoshi Yone
    TI__Genius 16870 points

    Yone-san,

    I cannot predict what would happen because I do not know what is on each board. My recommendation is to not do the swap. If the swap for some reason happens software should not turn on the LEDs. May be implement a ID check that can verify which board is which before proceeding to turn on the LEDs.

  • 0 in reply to Michael Green
    TI__Expert 3600 points
    Hi, Michael,

    Thank you for the answer! Sorry for asking complicated questions many times.

    The customer's application is PC. If the LED is removed from the PIMIC, can the PC recognize to remove the LED?

    Best Regards,
    Satoshi Yone
  • 0 in reply to Satoshi Yone
    TI__Genius 16870 points

    Maybe they could rig something up with the GPIOs but, it would require a uP or the Intel processor to control the checking for it and operation of the GPIOs. The PMIC will not detect the LED on its own.

  • 0 in reply to Michael Green
    TI__Expert 3600 points
    Hi, Michael,

    I received some more questions from the customer...　If it is necessary, I will post new e2e thread.

    - "Maybe they could rig something up with the GPIOs but, it would require a uP or the Intel processor to control the checking for it and operation of the GPIOs."
    We would like to confirm that If they rig something up with the GPIOs, can they control with or without LED by using software? Also I need to confirm that If they rig something up with the GPIOs, can they turn off "the board with LED"?

    - What is "ID Cheack"?
    - Could you tell me why WLED_S pin and WLED_OUT pin are Open/GND?

    Best Regards,
    Satoshi Yone
  • 0 in reply to Satoshi Yone
    TI__Genius 16870 points

    Yes, they would be building a system that would test for the LED insertion or probably easier solution is to have the system do a hand shaking to detect which board is connected. They can have 1 GPIO monitor a HIGH / LOW ID that would be a resistor option stuff high or GND. For example they could set the LED board to ID = high and non-LED board ID = low. GPIO on uC looks at this setting and determines if the LED board is connected or not. 


    WLED_SW is the input to the boost so, it should be GND for best termination.

    WLED_OUT is the output and should be float. This is usually to prevent any shorts if for some reason the converter is turned on and the VIN is applied. If the SW node is GND then, you could GND OUT as well.

  • 0 in reply to Michael Green
    TI__Expert 3600 points
    Hi, Michael,

    Thank you for the reply. Could you teach me the meaning of the "ID Cheack"? I'm sorry if I overlooked...

    Best Regards,
    Satoshi Yone
  • 0 in reply to Satoshi Yone
    TI__Genius 16870 points

    I meant ID check as in a mechanism that checks the type of board plugged in. They can have a GPIO from a controller read the ID setting to determine if its an LED board or not. When populating the board, they can populate the LED with resistor to GND and if the LED is not populated then they can populate the pull-up resistor.


    TPS68470_LED_Detection.pdf