Part Number: TPS65987DDJ
Hello there,
I created a thread with the same name about 2 months ago. The issue was not resolved and I was asked to provide my email address so that the engineer looking into the issue could reach out to me.
However, I was not contacted. Furthermore, the thread was somehow deleted. Below I am presenting again the problem:
When attempting to charge smartphones that request 5V, the USB-C-PD-TKT-EVM appears to be working fine.
However, when attempting to charge a chromebook that requests 15V, it gets stuck in an endless loop of events:
1. GPIO13 (plug) goes HIGH, correctly indicating a compatible device is connected
2. GPIO10 (N2) goes HIGH, correctly chaging the feedback of the buck converter and thereby requesting 15V
3. VBUS transitions from 5V to 15V
4. after 1 sec, all of the above 3 go LOW
The above process repeats continuously. It seems as if the PD contract is initially succesful, but for some reason it
resets shortly afterwards.
The same issue occurs when attempting to establish a contract of 9V to charge a Huawei P20 mate.
On the other hand, the USB-C-PD-DUO-EVM, which uses the TPS65987D, works perfectly fine. Therefore I am led to believe there is some issue with firmware of the TPS65987DDJ.
Furthermore, if the lid of the chromebook is closed and it is drawing less current, then USB-C-PD-TKT-EVM stabilizes at 15V and charges OK. As soon as the lid is opened, it goes back into the above cycle.
In comparison, the USB-C-PD-DUO-EVM remains stable on both conditions. I am attaching videos where the behaviour of both EVMs can be observed.
Below I am attaching all relevant information, including:
- Scope shots: Vbus (yellow), CC1 (Blue), Var DC/DC (Purple)
- PD logs taken from the CY4500 PD Analyzer
- Videos where the two Evaluation Modules are compared, and the erratic behaviour of the USB-C-PD-TKT-EVM is clearly illustrated
I am also attaching a snapshot of the thread I created back in October.
HP Chromebook 14-db0000na
(Please visit the site to view this file)
(Please visit the site to view this file)
(Please visit the site to view this file)
Kind regards,
Vyron