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Original question:

USB-PD-CHG-EVM-01: Can't work well

USB-PD-CHG-EVM-01: Can't get the TPS25750/BQ25798 to charge a 3S battery

Nicolas Armogathe
Prodigy 20 points
Part Number: USB-PD-CHG-EVM-01
Other Parts Discussed in Thread: TPS25750, BQ25798, BQ25792, TPS25751

Tool/software:

Hello, I just purchased the USB-PD-CHG-EVM-01 to charge a 3S battery (using sink capability only) using both "USBCPD Application Customization Tool" and "TPS25750 Application Customization Tool" from the cloud GUI to generate a configuration binary as follow : 

The binary file doesn't seem to work, so here are the steps I take:

1) power the EVM using a battery not completely discharged

2) flash the EEPROM using the Aardvark connector J5, CAT24C256 choosen as target on 0x50 adress, write and verify succeed

3) disconnect the battery 

4) insert a USB C PD capable charger, the TPS25750 should at this point read the EEPROM configuration and set up itself and the BQ25798 charger

Here the Stat LED blinks but not at the normal 1Hz frequency, on the other hand, the pace is altered, there is no duty cycle of 50% and the period seems to be 3 seconds.

5) when inserting the battery not completely charged, Stat LED stop blinking and PPHV Test point is at 0V, acting like a battery charge complete or battery charge disable.

        *TS jumper is applied, 3S jumper is applied

        *I have the EVM with a BQ25798 mounted on it and not a BQ25792 as others may have

I don't understand what I'm doing wrong here, and I'm not sure about the binary file and which cloud application I should use to generate it. I have seen in the past people having problems with binary.

This is a rather urgent problem for me, if you can help me out. 

Best regards,

NA 

  • +1
    Prodigy 20 points

    Update : the USB C source I used couldn't negotiate the required power, but I have another question: is it possible to ask for a 60W contract, but for the source of 27W max to supply its maximum of 27W instead of 0W, using this kit?

    This way, my battery will always be able to charge to the maximum power output from any PD source.

  • 0 in reply to Nicolas Armogathe
    TI__Mastermind 19625 points

    Hi Nicolas,

    I primarily support the USB-C PD products, and am not too familiar with the CHG-EVM as a whole, but I can help you work through the USB-C issues.

    Can you share the json file and GUI version(see browser link) that you are using?

    Nicolas Armogathe said:
    Here the Stat LED blinks but not at the normal 1Hz frequency, on the other hand, the pace is altered, there is no duty cycle of 50% and the period seems to be 3 seconds.

    Are you expecting a 1Hz blinking? Why do you expect it to be 1Hz? 

    Can you monitor the I2C lines and report if you see:

    1. The I2C eeprom being loaded from
      1. You should see the PD reading from address 0x50
    2. The BQ device being configured
      1. You should see the PD writing to address 0x6B

    If possible, it would be good to see the decoded I2C so we can confirm that the PD controller is programming the CHG-EVM properly.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    Prodigy 20 points

    Hi Christopher, 

    The problem has been solved and was due to a non-USB PD compatible charger, however I have another question concerning PD contract negotiation, if we request 60W but the source can only supply 45W maximum for example, what happens? Would the source supply its maximum? Is it the general way USB C is expected to work by default?

    Also, this evaluation board doesn't work in source mode, for any contract above 5V. You can see the following post which deals with this problem, but I don't think it's been solved yet.

    https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1278134/usb-pd-chg-evm-01-tps25750-not-sourcing-as-expected

    Best regards,

    NA 

  • 0 in reply to Nicolas Armogathe
    TI__Mastermind 19625 points

    Hi Nicolas,

    Nicolas Armogathe said:
    if we request 60W but the source can only supply 45W maximum for example, what happens? Would the source supply its maximum? Is it the general way USB C is expected to work by default?

    Basically, yes.

    For USB-C PD, what actually happens is the source will advertise it's power capabilities first, and then the sink will request the max power that meets the sink capabilities requirements.

    If, for example, a wall adapter offers a 5V/3A, 9V/3A, and 15V/3A set of Source PDOs(power data objects), and we have a usb-c sink device that has it's Sink capabilities set to 5V/3A, 9V/3A, 15V/3A and 20V/3A, The source will first advertise it's PDOs, and the sink will select and request the highest power contract that matches it's capabilities. In this case, the sink would request the 15V/3A contract.

    The sink should never request more power than the source offers.

    Nicolas Armogathe said:
    Also, this evaluation board doesn't work in source mode, for any contract above 5V. You can see the following post which deals with this problem, but I don't think it's been solved yet.

    Can you share the .json you are using? I will need to obtain a CHG-EVM to do some testing on my end.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    TI__Mastermind 19625 points

    Hi Nicolas,

    Another comment I would like to make is that we do not recommend using the TPS25750 for any new designs. We have released the successor part, the TPS25751, and it should be used for any new designs. It is p2p and feature compatible, but will require using a newer version of the GUI for configuration. There currently is not a CHG-EVM equivalent with the TPS25751, but you may be able to swap the ICs.

    Thanks and Regards,

    Chris