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BQ25672: Is this battery charge controller compatible with PD controller TPS25730?

Daniel Day
Prodigy 30 points
Part Number: BQ25672
Other Parts Discussed in Thread: TPS25730, BQ25798, TPS25751

Tool/software:

I have started a new design containing a lithium ion 2S battery (7.4V nom).  It is a sink-only device application in which I need to use USB-C connector for batter charging and the D+/D- for USB 2.0 data to an MCU.  Is my device considered a DCP or a different PD 3.x nomenclature?

My device needs a PD controller to negotiate with any PD 3.x compatible charger plugged into it using a USB-C cable. Could be a PC or a USB-C wall block charger. I want to deliver the highest VBUS voltage available of 5V, 9V, or 12V. But no more than 12V.  The maximum current the load will draw is 3A (during bulk battery charging) and <=1A during normal operation.  I've chosen the TPS25730DREFR for the PD controller and BQ25672 are the battery charger, and also as the regulated supply for the main system power (which is 7.4V).  Are my selected PD and battery charge controllers compatible together?  The TPS25730 data sheet indicates a few specific BQnnnnn battery chargers that it is compatible with.  However, the BQ25672 is not mentioned at all as either compatible or incompatible. But it seems like they should be if boot-strapping the defaults using ADCINx in the TPS25730D are set correctly. Currently I have them strapped as follows:

- ADCIN1 = 10k res to GND. (strap decoded to 0)

- ADCIN2 = Rdivtop 43.2k to 3V3_LDO, Rdivbottom 10k to GND  (strap decoded to 3)

- ADCIN3 = Rdivtop 43.2k to 3V3_LDO, Rdivbottom 10k to GND (strap decoded to 3)

- ADCIN4 = Rdivtop 200k to 3V3_LDO, Rdivbottom 10k to GND (strap decoded to 1)

According to the datasheet this strapping should result in power-up defaults for the TPS25730 as follows:

Vpphv_min = 5V

Vpphv_max = 12V

Ipphv_min = 3A

Ipphv_max = 3A

I2C Address = 0x20

 

Sorry to ask for a partial verification of my design, but can someone please confirm this is a good solution and strapped settings are correct?

  • +1
    TI__Guru**** 169236 points

    Hi Daniel,

    BQ25672 is a buck only charger.  If you want its SYS minimum output to be 7.4V and then follow the battery up to full charge (e.g. 8.4V in a 2S), then the charger needs at least 8.4V input.  In other words, it would work at 5V input.  You might change to BQ25798 which is buck boost charger.

    I'm sending to the USB team for questions about the port controller.

    Regards,

    Jeff

  • +1 in reply to Jeff F
    TI__Mastermind 37655 points

    Hi Daniel,

    Daniel Day said:
    It is a sink-only device application in which I need to use USB-C connector for batter charging and the D+/D- for USB 2.0 data to an MCU.  Is my device considered a DCP or a different PD 3.x nomenclature?

    DCP stands for Dedicated Charging Port which is a BC1.2 specific name indicating a power only port. The TPS25730 does not support BC1.2. For USB-C PD, you are a Power Sink and either a Data DFP or UFP. If you are using the TPS25730, the port will only advertise as a Power Sink and a Data UFP.

    Daniel Day said:
    Are my selected PD and battery charge controllers compatible together?  The TPS25730 data sheet indicates a few specific BQnnnnn battery chargers that it is compatible with.

    Where did you see that the TPS25730 only supports specific battery chargers? I took a quick look but could not find the section in the datasheet. The TPS25730 does not directly interact with the BQ25672, so there should not be any issues of one supporting the other. The TPS25730 will negotiate as a USB-C PD sink and upon successful negotiation, will provide a voltage on the PPHV pins from the USB-C port. The TPS25730 does not configure or control the BQ device.

    Your ADCINx configuration looks correct.

    Thanks and Regards,

    Chris

  • 0 in reply to Jeff F
    Prodigy 30 points

    Great catch!  I will switch to BQ25798.  And a pre-emptive thank you for the USB information.  I definitely need to know if the PD controller and battery charge PMIC can operate with the D-/D+ lines connected directly to separate microcontroller or if a USB mux/hub is necessary in addition to support PD handshaking for battery charging and allow the data pins to connect with my microcontroller as an endpoint to the singular USB-C connector.

  • +1 in reply to Christopher Lim1
    Prodigy 30 points

    Sorry for the confusion.  It was an online firmware PD controller programming tool (I don't recall the tools name) on the TI website for a previously selected PD controller TPS25751 before I switched to TPS25730 to simplify my design.  That tool listed only a few specific BQnnnn devices in the configuration wizard/questionaire. The BQ25672 was not in the list of supported chargers.  Regardless, it sounds like my question is no longer relevant since you confirmed that the PD controller does not configure the battery charge device.  Instead, it simply serves up the VBUS power coming in from the USB-C connector to the battery charge controller after PD negotiation completes.  That should work just fine. 

    And thank you for confirming that the D+/D- of the USB-C connector can connect directly to my microcontroller and are not needed for either the PD controller or battery charge devices for port configuration.