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[C5535] Power Consumption for USB vbus detect

sam lai
Prodigy 210 points

Dear All :

We're doing the power consumption control on C5535 chip.

The USB module need to much power while normal working.

Could the USB controller detect the vbus signal when USB controller is power down.

Or any possible way to detect USB cable insertion at low power consumption (1~2 mAH most).

Please help us this issue.

Sam.

  • 0
    TI__Guru*** 140055 points

    Sam

    Would you please elaborate a bit on the mechanism of USB controller is power down? Are you putting the controller in SUSPEND mode? Did you remove the clock to the controller? How do you achieve the low power consumption?

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 210 points

    Hi David : 

    Thanks for your reply.

    I shut the USB controller down by manipulate the C5535 register (USBSCR : 0x1c32).

    The register is filled as 0x804C. 

    The USB controller consume too much power on detecting vbus voltage only. 

    Is any possible way to detect the vbus voltage through USB controller under low power consumption.

    Sam.

  • 0 in reply to sam lai
    TI__Guru*** 140055 points

    Sam

    By shutting down USB module, the USB PHY is no longer in normal operation, VBUS voltage detection is not possible.

    You can detect VBUS voltage condition by looking at the VBUS bits in the DevCtl register. In order to detect VBUS voltage condition, the USBSESSEND and USBVBUSDET comparators need to be enabled thru the USBSCR register. Also, SRP fix time registers (SRPFIXTIME1 and SRPFIXTIME2) need to be programmed as well.

    When you say low power consumption, how much power are you looking for? What is the purpose for having this low power consumption requirement?

    Thanks
    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 210 points

    Dear David : 

    Thanks for your reply. 

    We saved much power consumption by shutting down the USB module on C5535.

    We're still doing some experiment for detecting VBUS voltage through USB module. 

    Could you tell us what's the minimum power does the USB module need for detecting the VBUS voltage ??

    The low power consumption is one of consideration in our project. 

    In our case, the board should consume total power under 20mW on music playback. 

    Sam.

  • 0 in reply to sam lai
    Prodigy 210 points

    Hi All : 

    Does anyone know the minimum power for USB module to detect the VBUS voltage ??

    Sam.


  • 0 in reply to sam lai
    Mastermind 7560 points

    Hi Champs,

    I also would like to make sure the min and max power consumption of USB_VBUS pin.
    The C5535 Datasheet does not have the data.  So, could you please let me know about it?

    Thanks in advance for your cooperation.

    Regards,
    j-breeze

  • 0 in reply to j-breeze
    TI__Mastermind 23785 points

    USB_VBUS is an analog I/O pin, it is goverened under the recommended operating current specification of +/- 4mA.

    Regards.

  • 0 in reply to Steve Tsang
    Mastermind 7560 points

    Hi Steve,

    Thank you for your prompt reply.

    Regards,
    j-breeze