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TUSB4020BI: PWRCTL_POL and PWRCTL1,2

K.Hamamoto
Guru 12155 points
Part Number: TUSB4020BI

Hi

I would like to know how PWRCTL_POL and PWRCTL1/2 behaves when the USB is pluged in.
On the datasheet, PWRCTL_POL and PWRCTL1/2 is sampled after reset. However I do not understand how it behaves at each pin.
If PWRCTL_POL = Pull down = Low, the polarity is "active high" and PWRCTL1/2 will be set to low. Is this correct?
Then , PWRCTL1/2 will be high whent USB is pluged in. Is this correct?
(This is our measurement result on the customer board actually.)

Does PWRCTL1/2 set to High (PWRCTL_POL=0) or Low (PWRCTL_POL=1) internally when USB is plugged in?
(I could not find on the datasheet about the those pin behaviors when USB is plugged in.)

Best Regards,

Koji Hamamoto

 

  • 0
    TI__Mastermind 19720 points
    The PWRCTL pins all have an internal pull down.

    "If PWRCTL_POL = Pull down = Low, the polarity is "active high" and PWRCTL1/2 will be set to low. Is this correct?"
    When PWRCTL_POL = Low the polarity is active high which means that if PWRCTL1/2 are high(by an external pull up resistor) the Power-on control /battery charging is enabled for downstream port.

    Does PWRCTL1/2 set to High (PWRCTL_POL=0) or Low (PWRCTL_POL=1) internally when USB is plugged in?
    When the host is plugged in the the PWRCTL1/2 go to the active level(e.g High for PWRCTL_POL=0 or Low for PWRCTL_POL=1)
  • 0 in reply to Michael.Walker
    TI__Guru 60870 points
    Hi Koji,

    If the PWRCTL pins are active high (PWRCTL_POL = low), when the USB host enumerates the hub, the PWRCTL pins will drive high.
    If the PWRCTL pins are active high (PWRCTL_POL = low), when the USB host is not connected, the PWRCTL pins will drive low.
    If the PWRCTL pins are active high (PWRCTL_POL = low), when the USB host is not connected and battery charging is enabled, the PWRCTL pins will drive high. Battery charging is enabled by a pull-up on the PWRCTL pin (it is sampled as an input after power on reset and then becomes an output) or through I2C/SMBUS.

    I hope this clarifies the behavior.

    Thanks,
    JMMN