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TUSB4041I: PWRCTRL_POL

Shinichi Inoue
Guru 22301 points

Part Number: TUSB4041I

Dear Specialists,

My customer is evaluating TUSB4041I and has a question regarding PWRCTRL_POL.

I would be grateful if you could advise.

---

About Pin 9 PWRCTL_POL

I am thinking TUSB4041I and TPS2001 CDGN (downstream of TUSB4041I) for USB Power Derivery.
According to the datasheet P.34 9.2.2.7 Clock, Reset, and Miscellaneous,

"The PWRCTL_POL is left unconnected which results in active-high power enable (PWRCTL1, PWRCTL2,
PWRCTL3, and PWRCTL4) for a USB VBUS power switch."

So I left open the pin9 and used it, but PWRCTL1(Pin 4), PWRCTL2(pin3), PWRCTL3(pin1) and PWRCTL4(pin64) were all Low.

When Pin 9 was pulled down, Pin 4, 3, 1, and 64 became High, and enabling power delivery.

Is it a correct description in the data sheet?

Could you please advise what is the problem?

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Mastermind 19720 points
    The PWRCTRL_POL pin should be held either low or high and not switched after reset. The PWRCTRL(1-4) pins can be configured to either be high or low to allow the port to deliver power when a host is not connected. If the host is connected the TUSB4041I will automatically deliver power to the active port.

    the statement in the datasheet is correct. If PWRCTRL_POL is held high or not connected(pin 9 has an internal pull up) the ports can deliver power when PWRCTRL(1-4) are high and not when the PWRCTRL(1-4) pins are low. If PWRCTRL_POL is held low with a resistor(1K) the ports can deliver power when PWRCTRL(1-4) pins are low and will not when the PWRCTRL(1-4) pins are high.
  • 0 in reply to Michael.Walker
    Guru 22301 points

    Hi Michael,

    Thank you for your reply.

    I'll shere your suggestion with the customer.

    If he has an additional question, I cousult you again.

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    Guru 22301 points

    Hi Michael,

    I sent your suggestion to the customer.

    He has additional questions.

    I would be grateful if you could advise.

    ---

    I have an additional question about your advise you mentioned last time, 

    "The PWRCTRL_POL pin should be held either low or high and not switched after reset. The PWRCTRL(1-4) pins can be configured to either be high or low to allow the port to deliver power when a host is not connected. If the host is connected the TUSB4041I will automatically deliver power to the active port."

    Is it possible to use it if the PWRCTRL (1-4) pin is pulled up with 4.7 kΩ?

    Actually, I can use it by putting 3.3 V directly on the PWRCTRL 1 pin, so I think that I was wrong somewhere.

But on the other hand, in Data Sheet P.31 (9.2.2.2 Downstream Port 1 Implementation), it is stated that you can use Battery Charge by pulling up.

    A corresponding excerpt of the circuit diagram is shown below. In the following condition, Pin 4 is not set to High.

    Could you tell me what is the problem and how to use properly.

    ---

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Mastermind 19720 points
    I am not understanding your question. Yes it is possible to connect PWRCTL1 to 3.3 or to use a pull up resistor to 3.3. the pull up resistor is so that a controller can change that pin from high to low. The schematic will work that you posted above.
  • 0 in reply to Shinichi Inoue
    TI__Guru 64326 points
    Shinchi,

    At reset the PWRCTL1/BATEN1 act as a input to our hub to enable battery charging based on the pull up resistor on this pin. After reset this pin will function as a output that will overdrive the pull up on the PWRCTL1/BATEN1 pin. When functioning as an output the PWRCTL1/BATEN1 pin will be able to control the EN pin of your power switch. (4.7kΩ is a good pull up resistor to use, PWRCTL1/BATEN1 cannont be connected directly to 3.3V)

    When a fault occurs and the OVERCUR1z pin is driven low, then PWRCTL1/BATEN1 pin will be asserted active high or active low. The state for the PWRCTL1/BATEN1 pin in this event is determined by PWRCTL_POL pin.

    Also port power will only be turn on in two cases if battery charging is disabled and the host on the UFP tell the hub to turn on power a port or if battery charging is enabled. With battery charging enabled you do not need a connection on the UFP.
  • 0 in reply to Malik Barton57
    Guru 22301 points
    Hi Marik and Michael,

    Thank you for your reply.

    I'll share your advise with the customer.

    When I get a feedback from the customer, I consult you again.

    I appreciate your great help.

    Best regards,
    Shinichi