STUSB1600 can't work as source

[Gerald_W]

Dear All,

Hello everyone, I used STUSB1600 as the type-c dual role type power management. When it works as sink type, it is good. But when it works as source type, it doesn't work. I found VBUS_EN_SRC always keep high. This is my design schematic, could you please provide some suggestions. Thank you so much!

Best wishes,

Gerald.

[Richard Li]

Is CCxDB pin1,5 cause problem?

If you don't need dead battery function, you may connect these pins to GND.

[Gerald_W]

Hi Richard,

Thanks for your replying. My system is powered by a 3.7v Li battery. I think I need to use the dead battery function. I am also considering VSYS cause the problem. Maybe I should connect VSYS to 5V or VBAT, not GND (in the schematic I am testing, I connected VSYS to GND, sorry for the confusion).

Best regards,

Gerald

[Richard Li]

Hi, Gerald,

For my experience, every power chip vsys use for inside engine, if no power, totally no function, your sink shouldn't work.

Even you need dead battery function, you may connect one 33K resistor between cc-ccxdb pins to GND, avoid noise cause problem ( outside device no cc pin control.)

(33K only cause 0.1mA current when signal high)

Regards,

Richard Li

[Richard Li]

Read datasheet, this chip vsys can connect to GND, my bad.

[Gerald_W]

Hi Richard,

No worries, and thanks for your replying. This point, VSYS, is a little confused. I will tried to rework the PCB that make VSYS connect to VBAT directly. 

Best regards,

Zikun Wei

[Richard Li]

BTW,  If you re-layout PCB, better add two vias for I2C, then you can read back register debug. 

[NBALL]

Hello

Could it be possible, please, to share oscilloscope waveforms of vbus-CC1-CC2-vbus_en_src ?
I'd like to see the behavior when sink is connected to your PCB (i.e when stusb1600 acts as source)

Thanks

Nathalie 

[NBALL]

Hello

33K to GND might affect correct behavior of STUSB1600: CC should be connected to its corresponding CCdb pin, when stusb1600 needs to close its power path in deadbattery mode.
Please follow datasheet properly to get correct behavior.

Best regards

Nathalie

[Gerald_W]

Hello Nathalie,
Thanks for your replying. I did some rough measurement and found VBUS to be 0v, CC1 and CC2 to be 0v, and vbus_en_src to be 5v. I will provide detailed waveforms later today.

Thanks,

Gerald