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BQ25170J: BQ25170J STAT Flashing

Masayuki Otawara
Prodigy 10 points
Part Number: BQ25170J


Tool/software: 

When charging the battery, the STAT indicator flashes every 180 ms and charging fails. 
(If there is no battery, it flashes every 100 ms.)

[Condition]
IN=5V
ISET=1 kohm / TS=10 kohm / VSET=27 kohm (to GND)
/PG=open
Battery: Keeppower 14500 1000mAh 3.7V 3.70Wh

What mode is the 180 ms flashing?
  • 0
    TI__Guru* 76666 points

    Hi Masayuki

    Can you send a schematic for review.

    Masayuki Otawara said:
    What mode is the 180 ms flashing?

    Can you take a scope capture of the STAT pin flashing vs voltage at OUT?

  • 0 in reply to Bill Johns
    Prodigy 10 points

    Dear Mr.Johns

    Thank you for your message.
    I attach sch and Wave forms (Normal & NG).
    (Maybe I mistaked 180ms & 100ms last week, sorry.)

    I don't understand triggers of phenomenon.
    This happens sometimes when I connect the USB.

    Best Regards

  • 0 in reply to Masayuki Otawara
    TI__Guru* 76666 points

    Hi Masayuki

    Thanks for the additional information.

    Non Battery looks normal, what is expected.  The Charge time is 30mS, set by deglitch time, STAT LED on.  Voltage rises to 4.2V and sets charge complete after 30mS, STAT LED off.  Output capacitor discharges below 4.2V - 0.1V, recharge point, and charge start again.

    Still checking on the NG Mode, we can see the voltage rise to 4.2V during charge, STAT LED on for 30mS.  Then it turns off for 100mS, voltage drops to recharge.  The rise and fall in voltage is very sharp pointing toward resistance between battery and charger.

    Do you have a current meter between charger and battery, have seen this cause problems with other customers?

  • 0 in reply to Bill Johns
    Prodigy 10 points

    Dear Mr.Johns

    Thank you for your reply.
    The operation of NG Mode has become clear to me by your explanation.

    I think, in NG Mode, the battery itself shuts down due to its protection function, which is thought to be causing the resistance to become high.
    →In waveform, ch4 is the current probe clamping battery line.

    I understand the situation, I will proceed with the analysis.
    Thank you for your cooperation.

    Best Regards