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bq24079 battery charger circuit cannot charge single Li-ion battery

KIM KI HAN
Prodigy 10 points

I don't know why this circuit cannot charge the battery.

battery is single li-ion (In the picture, battery is placed at J2 or J7)

help me. please.

  • 0
    TI__Guru 70796 points
    Hello
    Schematic looks OK.
    Is the charge cycle not starting at all or is the charge current low?
  • 0 in reply to Bill Johns
    TI__Guru 70796 points
    More info on the Schematic review:
    1.) TS -- 10k to ground, safe condition --OK
    2.) /CE -- ground -- OK
    3.) EN1 (low) & EN2 (Hi) -- ILIM sets input current -- OK
    4.) ILIM -- 750 ohms for 2A input current limit -- OK
    5.) ISET -- 1.13k ohms for 790mA charge current -- OK
    6.) SYSOFF -- Gnd -- OK
    7.) TMR -- Float -- OK
    8.) IN -- Filter cap 10uF -- OK
    9.) OUT -- Filter cap 10uF -- OK
    10.) BAT -- Filter cap 10uF -- OK

    Things to check:
    1.) The input current with no load on OUT this will be very close to battery charge current.
    2.) Voltage on battery -- 1.8V or less is battery short condition current limited to 7.5mA. 1.8V to 3.0 is pre-charge current limited to 10% of ISET or 79mA in this case. Above 3.0V the current will be 790mA. When voltage is near 4.1V current will decrease before completing charge at 10% of ISET.
    3.) If battery voltage is a square wave with 25mS high low it could be battery detection, see figure 32 and 33 in data sheet.