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[C5535] USB power domain control

Guru 24520 points

Hi community member,

Please let me confirm the following question.
[Question]

Is there any problem to control USB power domain (like USB_xxxx) Power On/Off during active or sleep mode on C5535?

Best regards.
Kaka

  • Hi Kaka-san, 

    I am not clear on this scenario. Can you please elaborate more on this requirement providing details on which USB supply you would like to control (On/Off ), when exactly, in which sleep mode and why  would also help.

    Regards

     Vasanth 

  • Hi Vasanth,

    Thank you for your comments.
    Now my customer consider the re-booting situation from RTC-only mode.
    In RTC-only mode, we need to remove the power for USB domain. Thus, we need to control the USB power domains.
    So, we would like to know whether there is any problem for controlling the USB power domain in any time.

    If you have any questions, please let me know.
    Best regards.
    Kaka

  • Hi Kaka-san,

    With respect to controlling the USB power (ON / OFF) in RTC only mode, this looks ok. But again this scenario is not verified and characterized, as in RTC only mode its expected to shutdown all power domain except for The RTC Core (CVDDRTC), RTC I/O (DVDDRTC), and LDO inputs (LDOI).

    Regards

     Vasanth

  • Hi Vasanth,

    Thank you for your response.
    In terms of power-up sequence to C5535, customer need to be satisfied with the USB domain sequence as below.
    > USB_VDDA3P3 and USB_VBUS (as seen by the C55xx) needs to be gated until the USB_LDO turns ON

    Right?

    Best regards.
    Kaka
  • Hi Kaka-san,

    Yes, the USB power up sequence must be followed for USB to function correctly.

    Regards

     Vasanth

  • Hi Vasanth,

    Thank you for confirming.
    My concern is cleared.

    P.S. If possible, please provide the answer for the previous my post...

    Best regards.
    Kaka