• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 64 subscribers
  • Views 191 views
  • Users 0 members are here
Support feedback
Options
Options

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.

BQ25750EVM：FAQs

Mulin Chou
Prodigy 90 points
Part Number: BQ25750EVM
Other Parts Discussed in Thread: BQ25750, BQSTUDIO, EV2400

Hi TI team,

I use BQ25750 EVM in a standalone operation without BQStudio.

I change R67 from 4.99K to 12k.(ICHG 10A-->4.16A)

Load: EL CV mode

Q1: VBATLOWV not in the SPEC.

Calculated the value of VBATLOWV is 18.54V~20.72V.

EL CV mode:  Precharge -> fast charge @ Actual value: 21V (not in the 18.54V~20.72V)

 

Load: 7S1P 18650 Battery

Q2:  When the CV mode, ICHG spikes.

Precharge -> fast charge -> Termination

7S1P充電data1.xlsx

Q3:  Termination current not in the SPEC.

Calculated the value of  termination current HW Limit (ICHG pin) : 10% x ICHG = 10% x 4.16A = 0.416A

 Actual value: 0.284A

Thank you,

Regards

  • 0
    TI__Mastermind 24170 points

    Hello Mulin,

    Thanks for being patient with the delay. I will get back to you by Wednesday.

    Best Regards,
    Ethan Galloway

  • 0 in reply to Ethan Galloway
    TI__Mastermind 24170 points

    Hello Mulin,

    Mulin Chou said:
    VBATLOWV not in the SPEC

    VBATLOWV is a percentage because the VBATLOWV voltage will change as the battery charge voltage setting changes.


    Mulin Chou said:
    When the CV mode, ICHG spikes.

    What's your test set up here? Are you using a real battery and have any registers been changed?

    Mulin Chou said:
    Termination current not in the SPEC.

    The termination current is in the spec. The accuracies of termination at 0.250A, 0.50A, and 1.5A are listed in the specifications table.

    Let me know if you have any questions about this or the datasheet.

    Best Regards,
    Ethan Galloway

  • 0 in reply to Ethan Galloway
    Prodigy 90 points

    嗨天才，

    Mulin Chou said:

    Q1: VBATLOWV not in the SPEC.

    我知道VBATLOWV是一個百分比。我想知道我計算的公差值是否正確？

    最小值：64.3% x 1.504V

    典型值：66.7% x 1.536V

    最大：69.0% x 1.566V

    Mulin Chou said:

    Q2:  When the CV mode, ICHG spikes.

    我在獨立操作中使用 BQ25750 EVM，無需連結 EV2400 和 BQStudio。

    我只是將 R67從4.99K 更改為 12k。

    我使用真正的18650 7S1P電池來測試充電功能。

    Mulin Chou said:

    Q3:  Termination current not in the SPEC.

    當我在 沒有連結 EV2400 和 BQStudio 的情況下進行獨立操作時。

    我只是將 R67從4.99K 更改為 12k。

    參考充電參數預設設置， 終止電流為10% x ICHG (10% x 4.16A=0.416A)。

    哪種容忍度適合？ +/-20%？

    謝謝，

    問候

  • +1 in reply to Mulin Chou
    TI__Mastermind 24170 points

    Hello Mulin,

    Q1. By the way, the MIN and MAX feedback voltage range refers to the range where you can set the feedback voltage with I2C. The charger uses a feedback voltage of 1.536V by default. Did you measure the FB voltage when the charger transitioned to fast charge mode? The charger transitions from pre charge to fast charge based on the FB voltage.

    Q2. Thanks for this information. We recommend setting EN_PFM=0 when terminating below 2A. I will get back to you if I find a method that works for standalone.

    Q3. I understand your question now. 10% x ICHG is the value at which the charger terminates. The ±20% value refers to the tolerance of the termination current. Let me know if this makes sense.

    Best Regards,
    Ethan Galloway

  • 0 in reply to Ethan Galloway
    Prodigy 90 points

    Hi Genius,

    Ethan Galloway said:
    Q1. By the way, the MIN and MAX feedback voltage range refers to the range where you can set the feedback voltage with I2C. The charger uses a feedback voltage of 1.536V by default. Did you measure the FB voltage when the charger transitioned to fast charge mode? The charger transitions from pre charge to fast charge based on the FB voltage.

    I not measured the FB voltage yet. 

    I only want to know the VFB tolerance of SPEC, When I use in a standalone operation 

    The VBATLOWV of MIN and MAX feedback Voltage is calculated below?

    Min.：66.7% x 1.504V

    Typ.：66.7% x 1.536V

    Max.：66.7% x 1.566V

    Ethan Galloway said:
    Q2. Thanks for this information. We recommend setting EN_PFM=0 when terminating below 2A. I will get back to you if I find a method that works for standalone.

    I had setting EN_PFM=0, and precharge -> fast charge -> Termination

    It's okay,

    Ethan Galloway said:
    Q3. I understand your question now. 10% x ICHG is the value at which the charger terminates. The ±20% value refers to the tolerance of the termination current. Let me know if this makes sense.

    It's okay,thank you.

     

    Thank you,

    Regards

  • +1 in reply to Mulin Chou
    TI__Mastermind 24170 points

    Hello Mulin,

    For the FB voltage of 1.536V, the Min, Typ, and Max are:

    Min.： 64.3% x 1.536V    =  0.988
    Min ： 66.7% x 1.536V    =  1.025
    Max： 69.0% x 1.536V    =  1.060

    The same mathematics apply to the other FB voltages. Let me know if that makes sense.

    Also, a valid clock signal to the FSW_SYNC pin will disable PFM.

    Best Regards,
    Ethan Galloway

  • 0 in reply to Ethan Galloway
    Prodigy 90 points

    Hi Genius,

    It's okay.

    Thank you very much.

    Regards