TPS65721: After removing usb power cable, device is stuck in CH_RESET mode (in reg CHARGER_STATE)

Hi Maxim,

I'm not exactly sure what the issue is here. It's not clear to me if the problem statement in the title reflects that of the description. Could you please provide your schematic and clarify the issue you're experiencing?

Best,
Emily

Hello, Emily.
Here is a schematic. 
The problem is that every time i disconnect charging cable i get an interrupt that CHARGER_RESET is Rising. (Charger State register holds value 0x40) 

Sincerely,
Maxim

Hi Maxim,

Thank you for providing your schematic. One thing to note is that you may want to increase the capacitance on VDCDC1 with a 10uF cap as opposed to 4.7uF cap. Would you be able to provide scope shots of VAC and VSYS as you unplug the USB cable? Have you conducted an A-B-A swap to see if this issue follows the chip?

Best,
Emily

Hello 
Sure, i'll send scope shots a bit later, but reset state is present even after multiple reads. Also, voltage on pin THRESHOLD is always 3.3 (already measured).

Sincerely,

Maxim

Hi Maxim,

Thank you for reaching out, and happy holidays. Our engineering team currently has limited staffing now through January 3^rd. We will provide feedback no later than January 7^th.

Regards,

Alex

Hi Maxim,

I don't immediately see a clear reason why the charger should be going into reset state. Have you already performed and A-B-A swap to see if this problem follows the chip?

Best,
Emily

Hello, Emily

Yes, it was the first thing we checked. After repeated reads the problem stays.

Sincerely,
Maxim

Maxim,

Can you attach a copy of your layout?

Best,
Emily

I have only a schematic at hand. Basicaly right now i check via i2c status of charger every now and then and it stays on reset.

Maxim,

Thank you for the response. We should be able to get back with you sometime tomorrow.

Regards,

Alex

Hi Maxim,

It may be difficult to find the issue without the full system layout if I can't find anything in the schematic that would initiate a charger reset upon disconnection. What do you read at register 02h (CHGCONFIG0) both before and after unplugging the charging cable?

Best,
Emily