• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 347 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ24298: interface with USB-C sch and i2c registers review; battery charge level

German Chykun
Prodigy 40 points
Part Number: BQ24298
Other Parts Discussed in Thread: BQ24297

We are currently designing and testing our pcb that has bq24298 pmic charger and usb type c connector. Basically, bq24298 supplies 3.3-4.2V to LDO that supplies 3.3V@150ma to our microcontroller. Our system has standard 14500 800mAh battery with 10K NTC (@ 25C). 

Last Thursday, I experienced a problem while connecting our pcb to charge battery from one standard usb port of my notebook. Basically, my pc broke after this event (it suddenly powered off and I never could power on again)!

During this test, I don’t remember very well if the battery was connected to the pcb.

Now I have a series of the questions below:

1)I use these parameters of the bq24298 I2C registers, to be able to charge battery in two hours (so we want to charge at 400mA-500mA per hour), and in any case we DON’T want to use otg future (we don’t want to use our system as a powerbank, so in any case we will output voltage to outside as maybe this was the reason why my notebook broke).

REG00 = 0x32

REG01 = 0x1A

REG02 = 0x00

REG03 = 0x11

REG04 = 0xB2

REG05 = 0xCC

REG06 = 0x73

REG07 = 0x4B

Can you review these registers and schematic below for our application?

After read again the datasheet, and see sch of the evb we applied following changes that we think are vital for correct function of the pcb and external charger.

2)Do you have some schematic/application note  that explains how to connect usb type c connector to the bq24298? If not could you help us to connect usb type c with bq24298? (basically how we should force lines of usb type c such as CC1/CC2/ TX/ RX and so on).

3)My last question is about charge level of the battery. I see in datasheet is it possible to know state of the charge during charging, but is it possible to know percents of the charge during the charge? Also, what about percentage of the battery without charger?

  • +1
    Prodigy 40 points

    Update! I see this thread so question number 3 is responded   https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1088414/bq24298-bq24298-measure-battery-soc   

    But we still need support with registers and sch review plus connection to usb type-c

  • +1 in reply to German Chykun
    TI__Mastermind 23805 points

    Hello German, 

    Thank you for reaching out via E2E. Let me first give feedback on your schematic. 

    -Since you do not want to use OTG function ever it is correct to connect OTG pin to GND. Since you will always have OTG connected to GND the 0.1uF cap (C23) to REGN can be removed. 

    -I do not understand why you have D+ connected to PSEL pin and D- connected to PG pin. We have other charger ICs which specifically interface with D+/D- lines, but the BQ24298 is not one of them. PSEL must be driven high to indicate an USB is connected or driven to GND to indicate a higher power adapter is connected.

    -PG pin is a status output. It should be connected in similar fashion to the STAT pin or left unconnected. It should not be connected to the USB D- line. 

    The rest of your schematic looks good. I have checked your register settings and do not see any issues. 

    2)The BQ24298 is not designed to interface directly with a USB type C connector, hence we do not have any example schematic or application note available. As you mention you can force certain lines to have the adapter work as you desire. Unfortunately I am not a USB type C expert, so I cannot comment on a recommended way to force those connections. If you want the full functionality of the USB type C input I recommend you look to use a USB type C controller IC as well as the charger IC. 

    Best Regards,

    Garrett 

  • 0 in reply to Garrett Kreger
    Prodigy 40 points

    Hello Garrett,   in TI evb I can see standard micro usb where D- is connected to PG and D+ to PSEL. That's why we connect this two signals to usb connector. We don't know for sure why it could be so. 

  • +1 in reply to German Chykun
    TI__Mastermind 23805 points

    Hi German, 

    Thank you for the explanation for the design decision. Please allow me to help clarify. 

    There are references to D+ and D- in the BQ24298EVM schematic because the EVB was designed to be able to work with the BQ24298 as well as similar ICs such as BQ24297. On BQ24297 PSEL and PG pins are replaced with D+ and D- pins instead. If you refer to table 3 in the BQ24298 user guide you will see that jumper connections are defined so the board works with PSEL and PG pins. 

    The BQ24298 is not defined to directly interface with a USB input, hence there is no pin to connect D+,D- or CC1 and CC2 of a USB type C. 

    Best Regards,

    Garrett  

  • 0 in reply to Garrett Kreger
    Prodigy 40 points

    Hello Garrett, I see in datasheet b24297 has direct connection to the micro usb connector. I think this ref. matches better to our design, but I still have to find out what to do with other usb type-c pins or change the connector to micro usb.  I think we will post our new schematic here again to the review

  • 0 in reply to German Chykun
    TI__Mastermind 23805 points

    Hi German, 

    Understood. I am happy to review your new schematic once it is available. For clarity since it is for a different part can you request the schematic review for your design with BQ24297 in a new thread. Please consider this thread closed. 

    Best Regards,

    Garrett