• State TI Thinks Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 3 answers
  • Subscribers 62 subscribers
  • Views 572 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.

BQ25619: BQ25619 and BQ25619E about voltage accuracy

Hardy Xue
Expert 3640 points

Part Number: BQ25619

Hi Team,

My customer have a voltage accuracy question for BQ25619 and BQ25619E.

When the register 0x04[7:3] is set to "00110" (4.1V), we measure differential Vreg on same FW, HW and temp.

The battery charge to 4.086V on BQ25619E and the battery charge to 4.105V on BQ25619.

Could you please provide comments as below question? Thank you.

1. We know E version and non-E version only a difference on boost mode. But I checked accuracy in datasheet and it look like difference.

2. Due to my customer's application temperature may use in ambient 80°C, do TPS25619 and BQ25619E still can meet 0.5% or 0.4% spec of Vreg?

3. Customer measure 4 pcs TPS25619E but all of Vreg are under typical value even close to minimum value. Is these result make sense? Also, the date code is okay or not?

4. Could you provide any suggestion to us to make 0x04 register setting and actual value are close each other?

Best regards,

Hardy

  • 0
    TI__Guru 60241 points

    Hardy,

    2. If Tj is over 85C, the VREG_ACC specs do not apply.

    4. How was the charge voltage limit (VREG) measured? For the date code, please check with the local CQE.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    TI__Expert 3640 points

    Hi Ning,

    Q2. If Tj is over 85C, the VREG_ACC specs do not apply.

    [Hardy]: Sorry for misunderstanding. My question is whether charging voltage accuracy will out of spec when Charger IC at 80C condition?

    Q3. How was the charge voltage limit (VREG) measured? For the date code, please check with the local CQE.

    [Hardy]: It was shown as previous table. The register 0x04[7:3] is set to "00110" (4.1V), but the measurements are close to minimum even out of spec.

    And how about below questions?

    Q1: We know E version and non-E version only a difference on boost mode. But I checked accuracy in datasheet and it look like difference. Do these 2 parts with differential Vreg_acc spec?

    Q4: Could you provide any suggestion to us to make 0x04 register setting and actual value are close each other?

    Best regards,

    Hardy

  • 0 in reply to Hardy Xue
    TI__Guru 60241 points

    Hardy,

    We are working on it.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    TI__Expert 3640 points

    Hi Ning,

    Thanks for reply. 

    If you have any finding on EVM, please let me know. Thank you.

    Best regards,

    Hardy

  • 0 in reply to Hardy Xue
    TI__Guru 60241 points

    Hardy,

    Q2. The spec on the EC table is based on the IC junction temperature. It is unclear our "Charger IC at 80C condition" refers to the IC junction temperature or the ambient temperature. Please note that ambient temperature is not necessarily the IC junction temperature.

    Q3. The accurate way to measure the charge voltage limit is to use a source meter (e.g. Keithley 2420 sourcemeter) as the battery simulator with no more than 1mV battery voltage step when the charger is close to termination.

    Q1: The two datasheets should be correct.

    Q4: It is still unknown if the customer measurements are correct or not.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    TI__Expert 3640 points

    Hi Ning,

    Sorry for late reply.

    I am still confused for your feedback.. 

    Q1: Do you mean BQ25619 and BQ25619E with differential Vreg_acc? BQ25619 is more accurate than BQ25619E? A m I correct?

    Q3: about your comments, "no more than 1mV" is for actual experiment or datasheet?

    Q4: Customer's measurement is that they replace battery with 10k ohm resistor and then measure voltage of resistor. The most important is that customer measure BQ25619 and BQ25619E by same method and measuring same test point. the result is shown as previous table.

    Best regards,

    Hardy

  • 0 in reply to Hardy Xue
    TI__Guru 60241 points

    Hardy,

    Q1: As you pointed out, the specs on the two d/s are different.

    Q3: The 1mV step on VBAT is to measure VREG accurately at the bench.

    Q4: Please verify the customer's measurement results on the EVM using a source meter (e.g. Keithley 2420 sourcemeter) as suggested earlier to check if you get the same or different results.

    Thanks,

    Ning

  • 0 in reply to Ning T
    TI__Expert 3640 points

    Hi Ning,

    Q3: Why is the error of VREG accuracy between datasheet(21mV@4.2V) and bench test(1mV) so big?

    Q4: Due to COVID-19, we are working from home now and I don't have enough equipment to test EVM. But as you mentioned at Q3, there is only 1mV error on EVM. It look like customer's board design with some problem? 

    Best regards,

    Hardy

  • 0 in reply to Hardy Xue
    TI__Guru 60241 points

    Hardy,

    Q3: The accurate way to measure the charge voltage limit VREG is to use a source meter (e.g. Keithley 2420 sourcemeter) as the battery simulator with no more than 1mV battery voltage step when the charger is close to charge termination. So 1mV here is not VREG accuracy, but one of the test procedures in order to measure VREG accuracy on the EVM. Please search online about how to use a sourcemeter for measurements.

    Q4: We are not sure if the customer measurements or the customer board design are ok or not before you solder the same IC onto an EVM and redo the VREG accuracy measurements using the method suggested in Q3.

    Thanks,

    Ning.