TPD3S716-Q1: what is status of VUBS_SYS and VIN when TPD3S716-Q1 is not powered and enabled and only VBUS_CON is powered by host PC

Hello Jinju,

What is the USB connector type? Is it a micro-B? 

Can you provide the full schematic file?

BR,

Seong

Hi Seong,

USB connector on IVI board is  348611406(molex) and another is standard type-a connector which can connected to PC.

here is more info about USB schematic I can provide. sorry for that I can not provide whole system schematic.

some marked points(green line) maybe can help you to understand the connection between USB connector and SOC.

Hi Jinju,

To clarify:

1. The board is powered off so nothing is supplying power to the VIN pin.
2. VBUS_SYS is still connected to the DFP, or PC.
3. VBUS_CON is still connected to the UFP. 

Is this correct?

And how long after the the board was powered off was the 3.8-4V measured on VBUS_SYS, VBUS_CON, and VIN? Can 3.8~4V still be measured after some time passes? 

BR,

Seong

Hi Seong，

1.yes

2.VBUS_SYS is connected to  DCDC converter in our system, so it is also powered off because there is no power on VIN pin

3.VBUS_CON is still connected to UFP and connected to PC host.

VBUS_SYS,VBUS_CON and VIN is always 3.8-4V when VBUS_CON is connected to host PC.

here is topology of our connection setup for your reference.

Hi Jinju,

VBUS_CON is an output and should be connected to a Sink/UFP device. If VBUS_CON is connected to a host PC (a Source/DFP), 5V is being supplied to that pin.

Is this behavior occurring on more than one board? 

BR,

Seong

Hi Seong，

Yes I know。 For normal use case, our IVI system USB port act as host(DFP).  In the period of development, we need this USB port act as device for android debug.

The behavior  is accurring on all our board.

I think the protector should have some function that can prevent VBUS_CON transfer the 5V to VBUS_SYS.

Hi Seong

Thanks for the support. We will find some new solutions for our use case.