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BQ24250: [BQ24250] Charging fail

Part Number: BQ24250
Other Parts Discussed in Thread: BQ27220

Dear Team,


We found the battery cannot be charged through BQ24250, so I read the register 0 to get the status.

The status is 0x34 means the STAT is Fault.

No matter I unplug or plug the battery, the value of register 0 always 0x34. 

Therefore, it is not impacted by battery.


I've attached the partial schematic, please check.

Could you guide us how to resolve it? Thanks.


battery info:

3.8V and 300mA.  


$ i2cget 1 0x6a 0
successfuly i2cget  bus:0x1 addr:0x6a reg:0x0 data:0x34
$ i2cget 1 0x6a 1
successfuly i2cget  bus:0x1 addr:0x6a reg:0x1 data:0xec
$ i2cget 1 0x6a 2
successfuly i2cget  bus:0x1 addr:0x6a reg:0x2 data:0x8d
$ i2cget 1 0x6a 3
successfuly i2cget  bus:0x1 addr:0x6a reg:0x3 data:0xf8
$ i2cget 1 0x6a 4
successfuly i2cget  bus:0x1 addr:0x6a reg:0x4 data:0x2
$ i2cget 1 0x6a 5
successfuly i2cget  bus:0x1 addr:0x6a reg:0x5 data:0xa9
$ i2cget 1 0x6a 6
successfuly i2cget  bus:0x1 addr:0x6a reg:0x6 data:0xe0

Many Thanks,


  • HI Jimmy,

    I see no obvious errors with the schematic.  The fault register is a reporting a TS HOT fault.  This means the voltage at the TS pin is too low.  What is the value of the thermistor inside the battery?  If you disable the TS pin in REG0x05 bit 3, does the charger start charging?



  • Hi Jeff,

    We appreciated your great support!

    The battery gauge is BQ27220, I checked the temperature is 28.85 °C, voltage is 4.064V.

    Do you have any idea what root caused the error status?

    Thanks a lot!


    The battery can be charged after set the Reg5 Bit3 to zero.


    $ i2cget 1 0x55 0x6
    successfuly i2cget  bus:0x1 addr:0x55 reg:0x6 data:0xd1
    $ i2cget 1 0x55 0x7
    successfuly i2cget  bus:0x1 addr:0x55 reg:0x7 data:0xb
    0xbd1 = 3025 = 302.5°K = 28.85°C 


    $ i2cget 1 0x55 0x8
    successfuly i2cget  bus:0x1 addr:0x55 reg:0x8 data:0xE0
    $ i2cget 1 0x55 0x9
    successfuly i2cget  bus:0x1 addr:0x55 reg:0x9 data:0xF
    0xFE0 = 4064mA=4.064V


    Many Thanks,


  • Jimmy,

    The battery thermistor can only be connected to either the charger or the gauge, not both.  If not using the charger TS feature, it must be disabled.  You can do that with matching resistor divider or with internal register.