TPS25750: pls check what makes the PD communication fail with TPS25750EVM and one adapter?

Hi Ken,

If I understand correctly, the customer is using two wall adapters with the TPS25750EVM, and one of them (#15) does not work properly.

1. Do they see #15 working properly with other usb-c sink devices?

2. Also, do they have the VBUS and CC line channels flipped? It seems unusual that CC2 is at 5-V and VBUS at 1.6V. I am going to assume they are flipped in my responses.

I can not tell much from the scope captures. All I can see is the CC line seems to be at a correct voltage, and VBUS is at 5-V, then attempting to transition to a higher voltage and failing. It looks like we are entering the initial 5-V contract, then attempting to transition to a higher voltage but it fails, the contract resets, renegotiates, and repeats.

3. If you can obtain a PD log between the two ports that would be very helpful.

4. Please try configuring the TPS25750EVM to be a 5-V sink only (15-W max) and report back if it can negotiate a stable 5-V sink contract. This will help to narrow down where the issue is occurring.

5. Please share similar scope captures for the Apple adapter that works correctly.

6. Please share the exact json the customer is using.

Thanks and Regards,

Chris

Chris

1. #15 adapter can work properly with other USB-C sink devices, such as HW mobile phone, XiaoMi mobile phone.

2.

3.Customer has no PD analyzer tool so that PD log can't be recorded.

4.after configure TPS25750D EVM in 15W sink only, #15 adapter can work well and can provide 5V/3.2A power.

5.will test later.

6.what is json? how can I get it?

7.More zoom in waveforms are attached, wish they can provide more information.

5164.15 No adatper unstable-TPS25750D-Autel.pdf

#2, yes, we have flipped TYPE C wire in tests. the issue still happens

Hi Ken,

Ken Zhang said:

.what is json? how can I get it?

When they create a configuration in the GUI, they can generate the .json using the export settings button.

Ken Zhang said:

#2, yes, we have flipped TYPE C wire in tests. the issue still happens

I was asking about how they labeled their captures. In the first pdf you shared, the blue trace(CH.2) was labeled CC2 and the yellow channel (CH1) was labeled VBUS. I think those labels are flipped. CH1 should be CC2 and CH2 should be VBUS.

Ken Zhang said:

4.after configure TPS25750D EVM in 15W sink only, #15 adapter can work well and can provide 5V/3.2A power.

That is helpful, It looks like the 5-V sink is working, but when we transition to 9-V sink, an issue occurs. From a PD messaging level, we won't be able to tell too much without a PD-log.

Can you try a couple things:

1: Capture I2C logs between the PD and BQ parts

2: Disable the BQ controller and try the 27-W configuration again.

Thanks and Regards,

Chris

Chris

                The secondary board with updated TPS25750 schematic is debugging now.

                Up to now, total 37 pcs of different brand type C PD adapters are tested.Total 4 pcs of adapters, including below #15 adapter, can’t negotiate with TPS25750D on customer board and also can’t negotiate with TPS25750D EVM which is configured as 9v@3A power sink only.

                To do further analysis with those adapters’ negotiation failure issue, customer needs to know if TPS25750D was already certificated according to “USB PD3.0 CTS ”, or any other customer who had successfully pass the certification according to “USB PD3.0 CTS”.

                And before customer plans to transfer to TPS25751, is TPS25751 already certificated according to “USB PD3.0 CTS”, too?

              Customer was already bought a PD analyzer and will arrive within this week. Then PD log can be provided

Hi Ken,

Let me check with the team on the certification.

Were you able to capture the I2C logs and disable the BQ controller?

Thanks and Regards,

Chris

Ken Zhang said:

1.how to capture the I2C logs between TPS25750 and BQ controller on the TPS25750EVM?    During tests in customer side,  "TPS25750 application customization tool" is used, and BQ controller on TPS25750EVM is already disabled. 

You could capture the I2C log with any I2C sniffer similar to a Saleae.

Ken Zhang said:

. today, TPS25751D EVM (without BQ controller) is used to test with the #15 adapter , the negotiation is still failure and the waveforms seems to be same as with TPS25750D EVM sent to you before. Maybe, PD logs must be captured and need you help to do more analysis.

Yes, the PD logs should help us know when the PD negotiation is breaking down.

Please share the json the customer is using with the EVM.

Thanks and Regards,

Chris

Chris

customer tested #15 adapter with TPS25751EVM. the PD negotiation is still failure which is same as that with TPS25750. but with SC2021A can negotiate well with  #15 adapter. The PD LOG message, PD log file and JSON file are attached. 

Pls kindly check them

PD LOG file can open by "power z lab 2.3" program. I am not assure you can download the program. you can try it. the instruction for open the PD log file is also attached.

15 No adatper unstable-TPS25750_1D-Autel-PD LOG.pdf

{
  "questionnaire": {
    "device": "TPS25751",
    "answers": [
      null,
      5,
      4,
      1,
      1,
      0,
      3,
      0,
      1,
      1,
      1,
      null,
      0,
      0,
      0,
      0,
      0,
      0,
      0
    ],
    "vendorId": "0000",
    "productId": "0000",
    "version": "1.0.0.2"
  }
}

{
  "questionnaire": {
    "device": "TPS25751",
    "answers": [
      null,
      5,
      4,
      1,
      1,
      0,
      3,
      0,
      1,
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      1,
      null,
      0,
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    ],
    "vendorId": "0000",
    "productId": "0000",
    "version": "1.0.0.2"
  },
  "configuration": {
    "data": {
      "selected_ace": [
        {
          "register": 6,
          "data": [
            0,
            0,
            0,
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            0,
            0,
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          ]
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        {
          "register": 22,
          "data": [
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        {
          "register": 40,
          "data": [
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        },
        {
          "register": 41,
          "data": [
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          ]
        },
        {
          "register": 50,
          "data": [
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        },
        {
          "register": 51,
          "data": [
            3,
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        },
        {
          "register": 55,
          "data": [
            62,
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        },
        {
          "register": 92,
          "data": [
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        },
        {
          "register": 112,
          "data": [
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        },
        {
          "register": 152,
          "data": [
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      ]
    }
  }
}

power z PD LOG instructions.pptx

Hi Ken,

Thanks for the info, I will review it and get back to you this week.

Thanks and Regards,

Chris

Thanks for the logs Ken, it seems like VBUS never rises to 12-V once the 12-V contract is negotiated. We are the sink correct? This seems to be an issue related to the source, from the messaging end, it looks like we do everything correctly. Once we send the request message, the source needs to accept, and should send a PSRDY once the 12-V is ready on VBUS. The PD logs never show the VBUS voltage rising to 12-V.

Do you know if the adapter is compliant with the PD spec? Could you send a link to the adapter?

Thanks and Regards,

Chris

we don't know if the adapter is compliant with PD spec. below is its link on AMAZON;

https://www.amazon.com/dp/B0C6LH4495?th=1;

Chris

would you like kindly help give your comments?

Hey Ken,

Is the link correct? I don't see a USB-C port on this device? It should only ever be negotiating 5-V if it is Type-A.

Thanks and Regards,

Chris

Chris

there is a Type C port on underside.

Hey Ken,

I think that is an LED, not a Type-C Port.

Going back to the issue an logs you provided, if we are acting as sink, our role in the PD communication is to request a PDO. The Source should be providing the correct voltage (12-V) once the PSRDY is sent, but this does not seem to be the case in the logs you sent which is why I beleive the source is non-compliant.

Thanks and Regards,

Chris

If the VBUS voltage is not at the expected voltage when the PSRDY is sent, we might fail upon connect.