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HD3SS3220: ON timing of VBUS Switch for DFP application

K.Yaita
Guru 29720 points
Part Number: HD3SS3220

Hi Team,

The datasheet shows DFP application as the following. 



Could you tell me assert timing of PS_EN (=EN pin of VBUS Switch)?
I believe the timing is after USB controller can detect ID pin is Low, then VBUS switch is "ON".
Is my understanding correct?

Best Regards,
Yaita / Japan disty

  • 0
    TI__Genius 16150 points
    Hi Yaita,

    The HD3SS3220 will debounce the CC pins and wait for VBUS detection before successful attachment. The nominal time for tCCDebounce is 168ms (Default), this time can be changed through DEBOUNCE register from 118ms to 168ms.
    Even, you can review the connection state diagram in the USB Type-C specification, basically the source is detected for tCCDebounce and then VBUS is detected.
    According to the USB type-C spec, the tCCDebounce has a min=100ms and max=200ms, hence the HD3SS3220 has 168ms of tCCDebounce for this parameter (maximum value for this device).

    Best Regards,
    Luis Omar Moran
    High Speed Interface
    SWAT Team
  • 0 in reply to Luis Omar Moran
    Guru 29720 points

    Hi Luis-san,

    Thank you for your reply.
    Thanks to you I unerstood tCCDebounce specification.

    However it is DFP application in this case and I would like to ask assert timing of PS_EN (=EN pin of VBUS switch) in Figure 11.
    I believe the assert timing of PS_EN should be subsequent to ID pin shows Low, otherwise VBUS_DET detects 5V that is from VBUS switch and determines UFP attachment altough it is DFP application.
    Is my understanding correct?

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Genius 16150 points
    Hi Yaita-san,

    Your assessment is correct. After the states I mentioned, the ID pin is asserted Low.

    Thanks,
    Luis
  • 0 in reply to Luis Omar Moran
    Guru 29720 points

    Hi Luis-san,

    I really appreciate for your kind support.
    I understood.

    Best Regards,
    Yaita