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BQ24230EVM: Termination issue

Jeffrey Chung1
Genius 3350 points
Part Number: BQ24230EVM
Other Parts Discussed in Thread: BQ24232EVM, BQ24232

Tool/software:

Hi Team,

There is a termination issue on BQ24230EVM. I think that the termination is not detected under condition of jumper setting as follows. JMP1=open, JMP2=low, JMP3=low, JMP4=low, JMP5=high. Please check the attachment below and let me know the reason why.

Charge current graph.pdf

Regards,

  • 0
    TI__Guru** 105870 points

    Hello,

    Due to the U.S. holiday our responses will be delayed, sorry for the inconvenience.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Mastermind 32180 points

    Hi Jeffery, 

    I have performed lab testing with the jumper configuration you provided and I observe the EVM able to terminate as expected. 

    Given this observation I have a couple follow-up questions. 

    -Can you confirm that JMP2 = low before providing power to the EVM? The IC checks whether TD (termination disable) pin is driven high or low at startup and does not react if the TD status changes during the charge cycle. 

    -Can you double check that you have BQ24230EVM and not the BQ24232EVM with ITERM pin functionality instead of TD pin functionality? Connecting ITERM directly to GND by setting JMP2= low would result in no termination on the BQ24232EVM. 

    Best Regards,

    Garrett 

  • 0 in reply to Garrett Kreger
    Genius 3350 points

    Hi Garrett,

    As I checked EVM with customer, it is BQ24232EVM you expected. The attachment is the customer's test conditions and questions about BQ24232. Please check it and provide your feedback.

    Questions about BQ24232.pdf

    Regards,

  • 0 in reply to Jeffrey Chung1
    TI__Mastermind 32180 points

    Hi Jeffery, 

    Thank you for confirming they are in fact testing with BQ24232EVM. Please see my comments on new questions below. 

    1) The charge current drop at Q1 point appears to be due to specific battery being tested. The same drop can be observed in the original charge current graph provided. In my testing of BQ2430EVM I do not see such a drop with same test conditions. From the perspective of the charger IC this drop in current at Q1 is not a concern because the device continues to charge until termination threshold. 

    2)Given termination threshold is approx. 35mA when charge current is 350mA and ITERM = float yes Q2 point looks to be termination point. 

    3)Pulsed charging behavior is not expected after termination. As long as VBAT > recharge voltage threshold (typical 4.1V) charge current is expected to remain at 0A. Can you help to provide a waveform of battery voltage, measured at EVM TP2 (not at real battery terminal) at this time customer observes "pulse charging"

    Best Regards,

    Garrett 

  • 0 in reply to Garrett Kreger
    Genius 3350 points

    Hi Garrett,

    Please check the voltage waveform measured at EVM TP2 and let me know the cause. Could you share your testing charge current data measured at EVM? Customer wants to know TI's testing data.

    Questions about BQ24232_2nd.pdf

    Regards,

  • +1 in reply to Jeffrey Chung1
    TI__Mastermind 32180 points

    Hi Jeffrey, 

    Thank you for providing the requested waveforms, they are quite helpful for understanding the pulsed current after termination. 

    The voltage waveform confirms the "pulsed charging" behavior is due to battery voltage falling below the recharge threshold (typ 4.1V) after termination occurs. The battery voltage falling below the recharge threshold starts a new charge cycle and that is why charge current increases to approx. 35mA. The device then terminates charge again shortly after and the cycle repeats itself. 

    The waveform confirms the BQ24232 is behaving as expected. The charger IC has no control over battery voltage drop after termination has occurred. In a final design on a PCB rather than testing with an EVM the voltage drop between BAT pin output and the actual battery terminals may be less and the pulsed charging behavior may not be a concern. 

    Best Regards,

    Garrett 

  • 0 in reply to Garrett Kreger
    Genius 3350 points

    Hi Garrett,

    Let me check it with customer on their board instead of EVM. Thank you for your support.

    Regards,