CCG3PA power delivery turn-around time

[JuOl_4441426]

We are developing for a CCG3PA in a dual-role hub type product.

Currently, I am seeing about 100 – 300 ms power-down time on usb-c power when we switch between a tablet powering the bus vs the tablet being powered from the bus.  I know that FRS is available on other CYPD chips, but not the CCG3PA.  But, is there anything we can be doing to speed-up that turn around time?  We are hoping to keep USB peripherals that are connected to the hub alive during the change in power direction.  Thanks for any help.

[YatheeshD_36]

Hello,

Do you have the cc logs for this. If yes please do share it.

Can you please let me know which firmware you are using. Is it an example firmware or a custom one.

Best Regards,

Yatheesh

[JuOl_4441426]

Thanks Yatheesh.  Below is a link to my EZ-PD Analyzer capture.

At 0 I plug a USB-C tablet into the powered dock.  The tablet starts charging.

At 25 I un-power the dock with the tablet still plugged into the dock.  At this point, the tablet starts powering the dock.

At 45 I re-power the dock. At this point, the tablet stops outputting power and then starts charging.

https://drive.google.com/open?id=124AdYcaSO5ndD851zsrldqUiXfctUPuA

When power is flipped, I see about a 100 - 300 ms down-time on the USB-C power bus.  This causes any peripherals on the dock to re-enumerate, which is not desirable.

Thanks for any help!

Justin

[YatheeshD_36 · Accepted solution]

Hello Justin,

When the dock is powering the tablet and the power is removed from the dock then there will be a power shutdown which is expected, because the CCG3PA will put up a dead battery termination and then the PD contract is re-established.

But when the CCG3PA is powered externally when the power is being drawn from the tablet, the CCG3PA should initiate a PR_SWAP to the port partner to become a source. Do you see the same behavior on different devices. Please do let me know which firmware you are using for the CCG3PA chip.

Best Regards,

Yatheesh