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Which IC to use for USB-C charging

Ibrahim Kamal
Intellectual 390 points
Other Parts Discussed in Thread: BQ25606

Hi,

For a new design, i need to charge a single cell lithium battery (14Wh) from a USB-C connector.

I don't need to sink 100W of power, anything more than 10W will do just fine. Also, I'ld like to be compatible with legacy chargers that can only deliver 1A @ 5V, etc.

So, I was hoping to find an integrated solution that handles:

  • USB-C PD (UFP only, for simplicity)
  • Lithium cell charger
  • Power Path - to deliver power to the system

I found the MAX14748 that looks quite close to what i want, but I'ld rather keep all my design with TI parts.

Do you have an all integrated solution for that?  

I couldn't easily find parts numbers that match my needs.

Thank you very much,

  • 0
    Intellectual 390 points

    I think I found what i need, the BQ25606.

    However, I'm a bit confused on how much is this IC compatible with USB-C connectors.

    From literature, it seems that USB-C should be backward compatible, yet I can't figure out how will the BQ25606 tell the USB host to send more current or more voltage if there are no way connect CC1 and CC2 pins of the USB port to the BQ25606.

    Thanks for your guidance on this.

  • 0 in reply to Ibrahim Kamal
    TI__Mastermind 30000 points

    Hi Ibrahim,

    Do you want to support any Type-C PD functionality? You do not have to support 100W of sinking for a Type-C PD application, but if you stick with just USB Type-C, the max you can sink is 15W (5V/3A). 

  • 0 in reply to Adam Mc Gaffin
    Intellectual 390 points

    Thanks Adam,

    Supporting Type PD or sikining 100W is not design target; 15W would be perfectly enough.

    How would i go about connecting a type C connector to the BQ25606 to get the most current out of the adaptor/host (what ever it is)?

    1. Is it enough to connect D+ and D- between Type C and BQ25606?
    2. Also, i should just connect CC1/CC2 together to ground via 5.1KOhm, right?

    Anything else that is USB-C specific i should worry about and that is not stated in the datasheet of the BQ25606?

    Thanks a lot,

  • 0 in reply to Ibrahim Kamal
    TI__Mastermind 30000 points

    Hi Ibrahim,

    Since you do no require any Type-C PD functionality, and only need a Type-C sink with charger functionality, I'm going to assign this thread to the team responsible for the BQ25606. They will be able to answer your questions better than I can.

  • 0 in reply to Adam Mc Gaffin
    TI__Guru**** 166626 points

    Hi Ibrahim,

    None of TI's charger at the moment can communicate directly with USB Type-C.  If you only need to sink with charger functionality at 5V and 3A, you will need to properly terminate the CCx pins, external to the charger, and then set the charger's input current limit to max of 3A by leaving the D+/D- lines floating and properly setting the ILIM resistor.  

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Intellectual 390 points

    Thanks Jeff.

    I totally understand what you suggest. But If i go this way (fload D+ and D-) and set ILIM to 3A, what will happen when the wall adaptor cannot provide 3A?  I couldn't find the answer to that question in DS.

    Since I want my system to work with any USB port, it seems to me that the proper design would be to:

    * Only sink 2.4A at max @5V (12W)

    * connect D+ and D- to the USB to allow for adapter detection

    Thanks for your confirmation.  

  • 0 in reply to Ibrahim Kamal
    TI__Guru**** 166626 points

    Ibrahim,

    The device has VINDPM feature which will prevent the charger from crashing the input source as explained below:

    8.3.2.4 Input Voltage Limit Threshold Setting (VINDPM Threshold) The device's VINDPM is set at 4.3V. The device supports dynamic VINDPM tracking which tracks the battery voltage. The device's VINDPM tracks battery voltage with 200mV offset such that when VBAT + 200mV is greater than 4.3V, the IINDPM value is automatically adjusted to VBAT + 200mV.

    Your method works too but limits input current to 2.4A.

    Regards,

    Jeff