TPS254900-Q1: Compatibility with iPhone 12 series

Hi Downey,

1. Yes, USB data switch inside the TPS254900 always on after the handshake.

2. Can you give more information for the disconnection. With TPS254900 when connect an iPhone 12 less than 20% battery: Is the data never connected, or it will connect at first, then for a while it will disconnect?

3. The compatibility test report are NDA confidential, can you check with your contacted FAE engineer?

Thanks,

Jianhua  

Hi Jianhua,

2. After about 2 seconds of data connection, the data is disconnected.

If iPhone12 is not in the low battery state, there is no problem.

Please contact me if you need any information.

Thank you.

Hi Downey,

What is the ST Channel in below waveform?

Jianhua

Hi Jianhua,

ST is STATUS pin. I think that the STATUS pin doesn't matter.

Thank you.

Hi Downey,

To understand more clear, can you help to check:

1. The voltage of VOUT pin, if it has any drop when the data disconnection happens?

2. Is this just happens on iPhone 12 Series? Not for previous version of iPhone series?

We will try to  check if we can duplicate this issue in our Lab.

Jianhua

Hi Jianhua,

1. The VBUS voltage does not drop. 1ch STATUS, 2ch Enable, 3ch VBUS, 4ch VBUS current

2. We haven't tested it with iPhone13 yet. Up to iPhone 11 series, no problem.

Thank you.

Hi Downey,

Thanks for your patience. It is hard for me to find an iPhone 12 to duplicate your issue.

Can you help to do more check:

1. Can you increase the ILimit (you can connect the ILimit directly to GND).  To avoid the current limit happens.

2. Can you monitor the Data lines, and to see if it really no any signal pass through the TPS254900 (check the data switches is really off?).

Jianhua

Hi Jianhua,

1. We will test your idea.

2. Yes, CPU can monitor the data line. But we don't know if it's TPS254900 or iPhone that disconnects the Data line.

Thank you.

Hi Downey,

1. Yes, please to check that. 

But from all the experiments you have done, I think the TPS254900 doesn't turn off the data switches, because there is no Fault happens. iPhone 12 may be the one to stop communication for power saving mode or something else. But it can communicate if bypass the VBus of TPS254900, so one more thing we can check is to compare the voltage and the current of VBUS waveforms with/without TPS254900, to see if there any difference to cause iPhone 12 to stop communication.

Jianhua

Hi Jianhua,

Thanks for your test information.

We did test iPhone12. Load current is 1.5A. However, the Carplay connection failed.

1. Please let me know the status of your test EVM. What are the values of the resistance and capacitor connected to the FB and CS pin of the LMR14030 & TPS254900? (Please let me know resistance of ILIM_LO and ILIM_HI.)

2. Can you tell me the model name of the USB cable for the test?

3. Attached our schematic. Can you set FB and CS pin with the same value as ours and test it?

TPS254900.pdf

4. We checked D+ and D- when connected to iPhone 12. But I don't know if it meet the BC 1.2 standard. Can you check it?

Thank you!

Downey Kim.

Hi Downey,

1. I used the EVM: https://www.ti.com/tool/TPS254900Q1EVM-817, please see the schematic for all the resistors and capacitors: https://www.ti.com/lit/ug/sluubi0/sluubi0.pdf?ts=1637050336916&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS254900-Q1%253FkeyMatch%253D%2526tisearch%253Dsearch-everything%2526usecase%253Dpartmatches

2. I used the cable comes with iPhone. My setup as below. I tried both: 1). Connect J2 the VIN come from LMR14030. 2). Connect J3, the VIN directly come from the VBus of USB connector of my PC. Both ways PC can recognize iPhone 12 (below picture is above 20% battery, but when I tested it was below 20%). 

3. To avoid LMR14030 impact, can you bypass it, and can you use PC directly provide VIN as my #2) experiment?

4. Since it can draw 1.5A, so it successfully finished BC1.2 handshake. After BC 1.2 message, the D+, D- will be used for normal USB data communication.

Can you try to directly communicate with PC, instead of Carplay? I cannot try Carplay in our Lab. Thanks.

Jianhua

Hi Jianhua,

We know that TPS254900 does not support DCP mode. But customers are guessing to enter DCP mode by looking at the handshake waveform.

Can you check the waveform?

Thank you.

Downey Kim.

Hi Jianhua,

Thank you very much for checking.

The customer asked an additional question.

1. Does TPS254900 support the APPLE FAST CHARGE 2.1A specification?

2. I received a TPS254900 compatibility test report from a local FAE. The test version is 2017.

Is there any latest test report? If not, do you have any plans to test it?

Thank you.

Downey Kim.

Hi Jianhua,

1. Does the TPS254900 mean that 2.1A charging support and data communication between Apple phones are not possible?

2. Do you know whether the iPhone Fast Charge 2.1A specification is data communication possible or impossible?

If data communication is possible, should IC and USB C-Type Connector satisfy USB Power Deliver Spec?

If data communication is impossible, do you need new parts that support Divider3 mode with USB A-Type?

3. Do you have TI's recommendation item for question 2?

I'm sorry, but the customer requested a report on all questions and answers.

Can you publish the report?

I'm sorry for asking a lot of questions and requests.

Thank you.