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Original question:

TPS25810: TPS25810 with USB data lines?

TPS25810: why TPS25810 can't communicate USB data lines at 5V/3A?

user3619629
Prodigy 70 points
Part Number: TPS25810
Other Parts Discussed in Thread: HD3SS3212, , TPS2546, TPS2514

Could you inform communication fail mechanizm?

We use TPS25810 by USB VBUS line and HD3SS3212 by USB communication line from SoC.

We have a trouble that our product can't communicate to iPhone when  TPS25810 is set CHG=CHG_HI =1(it is 3A setting),

however it can communicate to iPhone when TPS25810 is set CHG=1, CHG_HI=0(it is 1.5A setting) .

I found following article, it is written that it can't communicate 5V/3A.

But I'd like to know mechanizm why can't communicate

(e.g,  what data does  TPS25810  send via CC line to iPhone? then what is set inside iPhone?, etc).

And do you have solution to communicate with iPhone at 5V/3A setting(CHG=CHG_HI=1)?

  • 0
    TI__Mastermind 30000 points

    Hello,

    The TPS25810 does not touch the USB data and should not have any effect on the device not being able to communicate. The only difference internal to the TPS25810 between 5V/3A and 5V/1.5A is the pullup resistor value that the TPS25810 advertises on the CC pins.

    As far as the E2E post you referenced is using the TPS2546, which is a BC1.2 charge controller. Old iPhones cannot charge at 3A, with the highest current setting they can charge at being 2.4A. However, in order to charge at this mode, you put a constant voltage on the USB2.0 lines, eliminating the possibility of transmitting data via the USB2.0 connections. So in the post, I recommended that they keep the TPS2546 in CDP mode which would allow for 1.5A of current capabilities as well as the ability to transmit data.

    What I would recommend is to put the different data channels on an oscilloscope and see if the iPhone handles them differently when 3A capability is presented instead of 1.5A

  • 0 in reply to Adam Mc Gaffin
    Prodigy 70 points

    Dear Adam san,

    Thank you for your comment.

    We will confirm our issue using oscilloscope as your recommendation.

    I got information that iPhone version is iPhone XS.

    And more, I got following strange information;

    1. our product can communicate USB data : our product + (Type-A - Lightning cable) + Type A to C adopter

    2. out product can't communicate USB data : our product + (Type-C - Lightning cable)

    At first, can you confirm above by your side also?

    If we use Type A to C adopter, it can't send current setting via CC line, right?

    So I doubt current setting that it can't be set.

    If we use Type-C - Lightning cable, it can send current setting via CC line.

    PS

    Our product doesn't use TPS2514 and TPS2546.

  • 0 in reply to user3619629
    TI__Mastermind 30000 points

    Hello,

    That is interesting. What I would recommend to do is also connect an oscilloscope to the CC and DP/DM lines when a Type-A - Lightning cable is attatched, as well as when a Type-C - Lightning cable is attached. In the scenario of when the A to C adapter is connected, the TPS25810 would not advertise the current setting but the cable itself would. There is a pullup resistor internal to the cable that would be presented on the CC lines, which would be detected by the devices connected to cable.

    I am unable to replicate this on my end as we do not have a iPhone XS for testing.

  • 0 in reply to Adam Mc Gaffin
    Prodigy 70 points

    Dear Adam san,

    Thank you for your feedback.

    I monitored CC line and VBUS5V and current.

    As you mentioned, CC voltage is changed when I insert A to C adapter. And type-C - Lightning cable is same also.

    I will monitor CC line and DP/DM.

    So could you inform correct timing of CC line and DP/DM when we set 3A?

    We doubt handshake timing by CC line and DP/DM. So please inform us handshake timing by CC line and DP/DM.

  • 0 in reply to user3619629
    TI__Mastermind 30000 points

    There is no exact timing requirement for the CC lines when negotiating an implicit Type-C contract via Rp and Rd. There is a spec that outlines when VBUS has to be set to 5V after an Rp/Rd resistor has been detected but that/s it. If you are seeing 5V on VBUS in both scenarios then that is not the issue.

    Would recommend that you check other devices in the system. The TPS25810 does not touch the data lines at all, and changing the current advertisement will not change the functionality of the data lines.