BQ25792: Device not entering OTG mode

William Rolph

Part Number: BQ25792
Other Parts Discussed in Thread: TPS25750, , TPS25751

Tool/software:

I have a design with a TPS25750 and the BQ25792. The board successfully negotiates a voltage when a USB source is plugged in and uses it to charge the batteries. However, it fails to enter OTG mode when the source is unplugged. If I plug in a USB load which tries to negotiate a voltage higher than 5V , the TPS25750 sends an infinite loop of messages (reproduced in table 1) to the BQ25792. There is some slow activity on the SW pins but not proper switching operation.

The messages occur in a loop of this order, but the choice of 1st message is arbitrary.

Reg	Val	Reg	Val	Reg	Val	Reg	Val
0x10	0x80	0x16	0xc0	0x14	0x1c	0x10	0x80
0x14	0x1c	0x01	0x0690	0x0d	0x4b	0x14	0x1c
0x11	0x00	0x03	0x0064	0x0b	0x026c	0x11	0x00
0x12	0x00			0x12	0x40	0x12	0x00
0x08	0x08					0x08	0x08
0x09	0x01					0x09	0x01
0x01	0x0690					0x01	0x0690
0x03	0x0064					0x03	0x0064

Thank you

11 months ago

0 Jeff F 11 months ago

TI__Guru**** 167146 points

Hi William,

I recall that was some issue with the first version of the TPS25750 firmware. I have moved this thread to the team that supports the TPS part.

Regards,

Jeff

0 Aya Khedr 11 months ago in reply to Jeff F

TI__Mastermind 30412 points

Hi William,

Thank you for reaching out!

We recommend using our follow-on device, the TPS25751 for new designs. There are a couple of know issues found in the TPS25750 that are addressed in the TPS25751 specifically with the PD + battery charger pairing. Please see the following FAQ.

Best Regards,

Aya Khedr

0 William Rolph 11 months ago in reply to Aya Khedr

Prodigy 10 points

Hi Aya, thanks for the quick response. Is there any workaround for these issues? The TPS25751D is out of stock everywhere I've checked, and I would like to avoid having to redesign to use the TPS25751S as this for a senior design project due in a month.

0 Aya Khedr 11 months ago in reply to William Rolph

TI__Mastermind 30412 points

Hi William,

Could you please share the json file and schematics? I can take a look to see if there are any workarounds.

Best Regards,

Aya Khedr

0 William Rolph 11 months ago in reply to Aya Khedr

Prodigy 10 points

Hi Aya,

I've attached the schematics and configuration json. Thanks for taking a look.

{"questionnaire":{"version":"7.0.4.7","answers":[0,2,2,1,0,null,1,null,1,null,0,16.8,1,0.04,0.32],"options":{},"configID":"0000","vendorID":"0000"}}

0 Aya Khedr 11 months ago in reply to William Rolph

TI__Mastermind 30412 points

Hi William,

Thanks for providing. I will look into this and get back to you with some feedback tomorrow.

Best Regards,

Aya Khedr

0 Aya Khedr 11 months ago in reply to Aya Khedr

TI__Mastermind 30412 points

Hi William,

One suggestion I have would be to change the power path for PDO1 to PP3 (PPHV) instead of PP1 (PP5V).

Please let me know if you see improvement in behavior.

Best Regards,

Aya Khedr

0 Adam Mc Gaffin 11 months ago in reply to Aya Khedr

TI__Mastermind 30000 points

William,

I sent you a friendship request. Please accept this so that we can send a private message. Can help get you TPS25751D material.

0 Aya Khedr 11 months ago in reply to Adam Mc Gaffin

TI__Mastermind 30412 points

Hi William,

I will close this thread as the conversation has continued elsewhere. Feel free to open a new thread for further questions.

Best Regards,

Aya Khedr

0 William Rolph 11 months ago in reply to Adam Mc Gaffin

Prodigy 10 points

Thanks Adam and Aya for the help and offer, and apologies for my late response. I ended up going with a redesign using the S model since there were other board improvements - and the university paid for expedited shipping ;)

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BQ25792: Device not entering OTG mode