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HD3SS3220: CC and DIR keep high when plug in a device

Jim CHEN
Expert 4795 points
Part Number: HD3SS3220

Dear Team,

My customer use HD3SS3220 on desktop application. 

In previous generation of DT, they used ID pin of HD3SS3220 to control the external power switch.

This new generation, they use HUB's GPIO to control the external power switch. 

But now they saw an issue that CC and DIR pin still keep high when the device attaches.

 

In previous generation, it doesn't have the same issue. 

Is VBUS_DET the possible root cause? They tie VBUS_DET to VBUS through 909k pullup resistor. But now power switch is controlled by HUB.

Is there any timing spec that the power switch must turn on within the time after CC detection?

Please help to clarify this issue.

Thank you.

Regards,

Jim

  • 0
    TI__Guru 64326 points

    Hi Jim,

    What happens to the waveform with current gen platform when you flip the device? Is there a schematic that I can review? There seems to be something strange on DIR. What is the test device used and is this the same device used in both waveforms provided?