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TPS65994AD: PD DRP with Battery charging

Muhammad Awais
Intellectual 720 points
Part Number: TPS65994AD
Other Parts Discussed in Thread: BQ25792, TPS25751, BQ25790, TPS65988DK

Tool/software:

Hi, 

We are new to USB-C PD application. Our application will have a 3-4 cell battery (kind of notebook) with option to have USB-C PD to charge the battery and in absence of VBUS or if we are sourcing the power on VBUS (DFP). In both case we need to include the battery charging as well. I am assuming we may need a buck/boost kind of charger to support PD. 

I am currently exploring TPS65994AD as the PD controller but I am lagging info on what else do we need to complete this all. Can you please guide us if there is any reference design from TI to select the chips needed for this whole application. 

Please note that I am also checking BQ25792 like if we need this kind of charger along with our application. 

Thanks and regards,

Mat

  • 0
    TI__Mastermind 18305 points

    Hi Mat,

    Thanks for reaching out on E2E!

    The best solution here would be to check out the TPS25751!

    You can check out the product page here: https://www.ti.com/product/TPS25751 

    This PD also already has native support for your BQ device.

    Thank you,

    Kevin

  • 0 in reply to Kevin Kosta
    Intellectual 720 points

    Hi Kevin,

    Thanks for your response. Please clarify the following and I will appreciate it you can answer each of them as this will help me to finalize the selection. 

    1. I have quickly gone through TPS25751 and it looks nice. Please let me know if it supports Alternate mode? We don't it need it during our testing but we sure will be using it in actual product later on and I would like to have the PD controller that will take care of it. If TPS25751 is not supporting then please suggest what else do we need along with TPS25751 as if we are going to use it. Please note that our final product will be similar to a notebook. 

    2. I like more the TPS25751D due to its Integrated 20V, 5A, 16mΩ bi-directional load switch so if we are using it along with lets say BQ25790 then I am assuming in case of no external power and we are the source (from battery) then BQ25790 will provide 5-20V on VBUS as shown below. Please confirm if this is correct?

    3. Looks like BQ25790 is out of stock and its also a BGA so I would like to go with BQ25792 due to its availability and package. Please confirm that both of these have to be connected with the TPS25751 via I2C without any other controller (MCU) and TPS25751 will be communicating and controlling the BQ?

    4. BQ also has USB interface for Bus detection. Please confirm that if it is mandatory? I am asking this because in our case if we want to connect any peripheral like external USB keyboard then we are suppose to use this USB D+/- to communicate with our processor while sourcing the charge from VBUS. In this case connecting USB D+/- from USB-C to this BQ doesn't make senses as we have to use this USB D+/- to communicate between keyboard and our processor. 

    5. Based on 1. if you think TPS25751 is not suitable then please suggest the other options that also supports battery chargers from TI. 

    Kind regards,

    Mat

  • 0 in reply to Muhammad Awais
    TI__Mastermind 18305 points

    Hi Mat,

    Thanks for reaching back out!

    This device does not support ALT mode. Since that is the case, the best PD controller to use here would be the TPS65988DK. It supports Alt modes, but you would have to handle the writes to the BQ between the PD. There is an I2C controller events table that you can use to make the writes for whatever BQ device you select.

    Thank you,

    Kevin

  • 0 in reply to Kevin Kosta
    Intellectual 720 points

    Thanks Kevin for your reply.

    TPS65988DK looks good. I would appreciate if you may answer the rest of the questions from my last post, specially for point 2 and 4. 

    Also, for writes to the BQ between the PD do I need to control them via an MCU? Like a MCU as master with TPS65988DK and BQ on same I2C?

    Kind regards,

    Mat

  • 0 in reply to Muhammad Awais
    TI__Mastermind 18305 points

    Hi Mat,

    Sounds good!

    I will get to the BQ questions by tomorrow.

    Regarding writes you can use either the PD or MCU! There is an I2C controller events table on the PD config tool that you can use to have the PD write to the BQ.

    Thank you,

    Kevin 

  • 0 in reply to Muhammad Awais
    TI__Mastermind 18305 points

    Hi Mat,

    Sorry for the delay here!

    Muhammad Awais said:
    2. I like more the TPS25751D due to its Integrated 20V, 5A, 16mΩ bi-directional load switch so if we are using it along with lets say BQ25790 then I am assuming in case of no external power and we are the source (from battery) then BQ25790 will provide 5-20V on VBUS as shown below. Please confirm if this is correct?

    Yes that is correct!

    Muhammad Awais said:
    3. Looks like BQ25790 is out of stock and its also a BGA so I would like to go with BQ25792 due to its availability and package. Please confirm that both of these have to be connected with the TPS25751 via I2C without any other controller (MCU) and TPS25751 will be communicating and controlling the BQ?

    In your case, either the TPS65988DK will control it via I2C or it will be controlled via an external MCU if you would like.

    Muhammad Awais said:
    4. BQ also has USB interface for Bus detection. Please confirm that if it is mandatory? I am asking this because in our case if we want to connect any peripheral like external USB keyboard then we are suppose to use this USB D+/- to communicate with our processor while sourcing the charge from VBUS. In this case connecting USB D+/- from USB-C to this BQ doesn't make senses as we have to use this USB D+/- to communicate between keyboard and our processor. 

    Let me double check but it might actually be used for BC1.2 charging. If you are connecting and using the USB2 lines, I would not have them connected to the BQ device. 

    Thank you,

    Kevin