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BQ24103: BQ24103 part Dead

KIM Andy
Expert 2530 points
Part Number: BQ24103


We will inquire about BQ24103.

Input and output conditions
1. Input: 12V / 2A
2. Output: 8.4V / 1A


problem
BQ24103 VCC and GND SHORT during IC charging.
The phenomenon appears after 3 to 6 months of use by consumers.
What kind of things do you suspect?

It is currently composed of (Charger → Battery → booster).

The corresponding circuit diagram.

  • 0
    TI__Intellectual 1980 points

    Hello,

    Why your FB pin is connected to VIN? FB is for output voltage analog feedback adjustment.

    Regards

  • 0 in reply to Kerry Song
    Expert 2530 points

    HI

    thank you for the reply.

    The pin name of the circuit diagram attached above is incorrect.

    Sorry. I will attach the schematic again.

    Please check with the modified circuit diagram.

  • 0 in reply to KIM Andy
    TI__Genius 14760 points

    Hello,

    There are some questions need your confirmation,

    Q1 : What is the battery spec.?(?S?P, charging current, charging voltage...etc.)

    Q2 : Could you provide the situation for this short issue? You mean it worked normally in the beginning. After 3-6 months, VCC shorts to GND without any weird behavior?

    Q3 : Is this issue a single case or there other similar phenomenon happen in your design?

    Thanks,

    Ann Lien

  • 0 in reply to Ann_Lien
    Expert 2530 points

    hi,

    Q1 : What is the battery spec.?

    A1 :

    Applied Battery
    Battery type: Li-ion Battery
    Battery Specification: ICR18650B4
    Manufacturer: LG chem.
    Battery capacity: 2,500 mAh (0.2 C discharge)
    Normal voltage: 3.6V
    Termination voltage: 2.75V
    Internal resistance: 100mΩ or less
    Weight: 48.0 g max

    Battery Pack Charging Condition
    Charging voltage: 8.4V 0.05
    Charging current: 1250mAh, Maximum charging current: 2500mAh, End current 200mA
    Charging method: CC-CV Mode
    Charging time: About 7hr

    Battery Pack Spec
    Normal voltage: 7.2V
    Discharge end voltage: 5.5V
    Normal capacity: 7,500 mAh [2S3P]
    Maximum discharge current capacity: 5A
    Internal resistance: 350mΩ or less

    Operating temperature:
     1) Charging: 0  + 45C
     2) Discharge: -20  + 60C
     3) Storage: -20  + 45C (short-term storage)
     4) -20  + 20C (long term preservation)

    Q2,Q3 :

    A : When the user charged the battery in the evening after consuming the battery, the defective was confirmed the next morning.

    I do not know the exact cause of this, and I would like to make this phenomenon arbitrarily.

  • 0 in reply to KIM Andy
    TI__Genius 14760 points
    Hello,

    According to your charging requirement, there is no big error in your design.
    Have you tried to duplicate this issue?
    The only defective is Vcc short to GND or there are other mistake?
    Could you please provide us some waveform to find the clues of this issue? We want before/after this issue situation with waveform then we can find out the root cause easily.

    Thanks,
    Ann Lien
  • 0 in reply to Ann_Lien
    Expert 2530 points

    HI,

    We tried to make the same issue arbitrarily, but we could not create it.

    We will deliver the measured waveform.

    Measurement based on battery voltage

    CH1 : pin4(IN), CH2 : pin20(OUT), CH3 : battery

    Battery Voltage : 5.45V

    Battery Voltage : 6.47V

    Battery Voltage : 6.93V

    Battery Voltage : 8.07V

    Battery Voltage : 8.17V

  • 0 in reply to KIM Andy
    TI__Genius 14760 points
    Hi Kim Andy,

    So these waveform is from the normal IC, right? If this issue occurred in many units, we will consider it is IC fault to make system works abnormal. Since we could not duplicate this issue, plot waveform to analysis, and could not make sure the failure situation, we could not know what exactly the root cause is. Could you help me to confirm the failure situation(? fail units/? units) Try to duplicate the issue again to plot waveform. We really want to help you but we could not find the clues without any waveform or information on it. Thanks for your help.

    Thanks,
    Ann Lien
  • 0 in reply to Ann_Lien
    Expert 2530 points

    Hi Ann Lien,

    The battery voltage of all defective products is measured at 7.25V.
    We have done a temperature test when charging. At about 7.4V stopped charging. The power was turned off and after 1 hour, it was recharged and it was fully charged to 8.4V.
    Could this be the cause of the problem of the product?

    Temperature measurement result.
    Vbat       time    Temperature
    6.267V   11:43      36 ° C
    6.972V   12:00      47 ° C
    7.058V   12:15      50 C
    7.147 V   12:47     52 C
    7.318V   13:47      53 C
    7.403V   14:53      55 C

    Stop charging in the middle (cause unknown)
    7.4V restarts at 16:19
    7.911V   17:53      56 ° C
    8.291V   19:18      53 ° C
    8.396V   19:56      43 ° C

  • 0 in reply to KIM Andy
    TI__Genius 14760 points

    Hi Kim Andy,

    For TS pin of bq24103, did you connect this pin to battery thermistor or just one voltage divider as your schematic?

    You can refer to datasheet "Temperature Qualification". If TS voltage is below hot threshold, charging would be suspended. You can also measure TS voltage to see if temperature is the key point to make charging stop.

    But even if temperature causes charging suspended, it is protection function and should not damage Vcc pin. Could you please confirm the failure situation? Is there only Vcc pin short to GND or any other component or pin damaged? If there is another failure followed with Vcc damaged, we can analysis the root cause by the relation between them.

    Thanks,

    Ann Lien

  • 0 in reply to Ann_Lien
    Expert 2530 points

    As shown in the circuit diagram above, the ts pin is connected by a resistor.
    We did not use a thermistor.
    VCC is shorted to GND in all current defects.
    What parts should I identify?
    Should have to check the VCC voltage at the time of charging is stopped?

  • 0 in reply to Ann_Lien
    Expert 2530 points

    As shown in the circuit diagram above, the ts pin is connected by a resistor.
    We did not use a thermistor.
    VCC is shorted to GND in all current defects.
    What parts should I identify?
    Should have to check the VCC voltage at the time of charging is stopped?

  • 0 in reply to KIM Andy
    TI__Genius 14760 points

    Hi Kim Andy,

    Please check all bq24103 pin and output component. I want to confirm if there is any other failed component or pin since I want to see if another failed component's or pin's root cause damages Vcc pin. I have no idea why Vcc would short to GND.

    And yes, please check the Vcc voltage when charging stops.

    Thanks,

    Ann Lien

  • 0 in reply to KIM Andy
    Expert 2530 points

    Hi

    we have been experiencing a constant problem and I have tested "decap test". Will you ever be inferred that a problem?

  • 0 in reply to KIM Andy
    TI__Genius 14760 points

    Hi Kim Andy,

    Is this a failure analysis report? Could you send it to ann_lien@ti.com? I can discuss with our team based on this report.

    Damaged should be caused by over-current or over-voltage. And Vcc is connected to input power through diode. Could you please check if there is any OV or OC occurred at Vin or diode?

    Thanks,

    Ann Lien