• State Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 552 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

BQ25883: BQ25883RGET on custom circuit charges slow

Nils Minor
Intellectual 290 points
Part Number: BQ25883
Other Parts Discussed in Thread: PCM2900

Hi Ti-Experts,

I have made a custom circuit based on thw BQ25883. When powering it up trough the USB C connector I only get a charging current of 0,287 A. The BQ25883 shares it's D+/D- lanes with an PCM2900CDB. Please see the schematic below.

When connecting the USB C cable the device starts to charge and indicates this by the BQ_STAT signal that goes low. However, why is the design charging with this less current? I need 2A charging and I set ILM to >3A. Any suggestion why my design is not working as expected?

Note : I did not set anything via I2C, I use the BQ25883 like set from TI.

UPDATE :

I was able to read out the chip via I2c :

data at 0 : 10100000
data at 1 : 1011110
data at 2 : 10000100
data at 3 : 100000
data at 4 : 100010
data at 5 : 10011101
data at 6 : 1111101
data at 7 : 10
data at 8 : 1101
data at 9 : 11110110
data at 10 : 0
data at 11 : 1001011
data at 12 : 11010000
data at 13 : 0
data at 14 : 0
data at 15 : 1001001
data at 16 : 10010000
data at 17 : 0
data at 18 : 0
data at 19 : 0
data at 20 : 0
data at 21 : 110000
data at 22 : 10
data at 23 : 0
data at 24 : 0

When I plug in the Charger and then insert the  batteries the charges is able to charg with 0.8A. Any Idea what this could be?

Thanks,

Nils

  • 0
    TI__Genius 10385 points

    Nils,

    I would be happy to help debug your issue, but I am unable to see your schematic. Please try attaching it again.

    My apologies,

    Ricardo

  • 0 in reply to Ricardo
    Intellectual 290 points

    Hi,

    thanks for mention this and sorry I thought the images would be there.

    Here is my circuit:

  • 0 in reply to Nils Minor
    Intellectual 290 points

    Hi TI-Experts,

    any idea about my charging issue? Why is it only 0,28A. FYI I measure the current on the battery side between +BATT and the first battery pole.

    Thanks for any help,

    Nils

  • 0 in reply to Nils Minor
    TI__Genius 10385 points

    Nils,

    Based on your register output I notice a few things. 

    First, you appear to be in IINDPM. This means your BQ25883 is hitting its determined input current limit and as a result the charging current will be reduced. IINDPM is selected to the lowest value of the IINDPM register, D+/D- detection, ICO and ILIM.

    Next, let's consider D+/D-. Your VBUS Status is indicating "Unknown" so the D+/D- current limit will be set to 500 mA. The "unknown" status is indicative of D+/D- failing to identify the adapter.

    I suspect this is due to sharing the lines with PCM2900CDB. Please provide a scope capture of the D+/D- handshake from the perspective of the BQ25883 (that is to say as close to the IC as possible). Remove the PCM2900CDB and then recapture.

    Thanks,

    Ricardo

  • 0 in reply to Ricardo
    Intellectual 290 points

    Hi Ricardo,

    thanks for your response! Ok that make sense to me as when I plug the device in, without battery (the PCM2900 is off) the device charges with 0,8A so it might be the PCM2900 that tries to communicate over the same USB lanes. This is a problem for my application and it is difficult to me to remove the PCM2900.

    Is it possible to disable the D+/D- detection and to just set the max curent to 1A via I2C? That would be a good solution to me :) Or how would it be possible that the BQ and the PCM29 share the same USB lanes (I only have one connector)

    Thanks for your help,

    Nils

  • 0 in reply to Nils Minor
    TI__Genius 10385 points

    Nils,

    I have two solutions for you.

    Solution 1: Disable D+/D- and rely on ICO, ILIM, or IINDPM to set the current limit

    To disable D+/D- you will need to short the D+ and D- pins on the BQ25883 and rely on the lesser of ICO, ILIM, or IINDPM.

     ICO: (Details of operation), this algorithm will execute by default and set the input current limit based on the available input power. To disable it, the host controller must set the EN_ICO to 0.

    ILIM: The current limit is set in hardware using a resistor.

    IINDPM: The current limit is set in software using the IINDPM register.

    Please remember that the BQ25883 will choose the lesser of these three values to set the input current limit.

    Solution 2: Mux the D+/D- lines

    Using additional external circuitry you could have the D+/D- lines connected to the charger by default and then mux the the D+/D- lines after the BQ25883 asserts an INT to let the host know input source detection has completed. 

    I think solution 1 might be a better fit.

    I hope this resolves your issue,

    Ricardo

  • 0 in reply to Ricardo
    Intellectual 290 points

    Hi Ricardo,

    thanks for your feedback! I tried your first suggestion and it is working! The system charges with up to 1,5A depending on the charger, thats great !

    I only have one problem. When connecting the sytsem to an USB 2.0 connecotr on my PC, I see the 1Hz blinking fault detection, so it is not chagring. That would be no problem but it makes sounds on the Audio interface (PCM2900) and that is not good.

    Any Idea how to prevent this behaviour? Mybe reading out a register, getting an error and switching it down?

    Best regards,

    Nils

  • 0 in reply to Nils Minor
    TI__Genius 10385 points

    Nils,

    Could you provide the register output when connected to the USB2.0 connector? If possible, could you provide the values as hexadecimal instead of binary?

    Thanks,

    Ricardo

  • 0 in reply to Ricardo
    Intellectual 290 points

    Hey,

    thanks for your feedback, it now seems like it is working ^^ I was not able to get the faulty blinking.

    Best regards,
    Nils