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BQ24158: Low Charging Current

Baghiya Lakshmi
Intellectual 645 points
Part Number: BQ24158

Hi,

We are using the battery charger BQ24158FFT in our design. Our targetted charge current is 100mA and we are using the Rsns as 820mE. But it is only taking 30 mA as charging current.

Below is the register configuration maintained

Memory Location
Charging Boost
0x80 (Reset) 0x80 (Reset) 0x00
0x38 0x39 0x01
0xA/0x8E 0xB 0x02
0x03
0x9 0x9 0x04
0x24 0x24 0x05
0x40 0x40 0x06

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/652953/bq24158-could-not-charge?tisearch=e2e-sitesearch&keymatch=BQ24158#

By referring to the above case, we tried the new configuration of register 2 as 0x8E as suggested but still no change in charging current. Please suggest us how to resolve the issue.

In the datasheet, the register configuration is not clear. Also, I checked the user guide of EVM as well. Can you share any document with complete details of the register configuration.

Thanks in advance

Baghiya

  • 0
    Intellectual 645 points

    Hi,

    We are unable to configure registers 4 and 6 as below

    04 - 0x7B (configured only to 4B)

    06 - 0x80 (configured only to 40)

    Thanks in advance,

    Baghiya

  • 0 in reply to Baghiya Lakshmi
    TI__Guru**** 151946 points

    Hi Baghiya,

    Register 06 can only be written to once after the IC's CSOUT pin (i.e. the battery) rises above 2.0V.  It sets the max charge voltage and current in Registers 02 and 04.  After that write, that register is locked until CSOUT pin falls below 2.0V and resets.

    The registers reset to defaults if the WD timer expires.  It appears that are periodically/continuously writing 0x80 to reg 0x00 in the table above.

    Register 04 and 02 can be rewritten as long as there values are not higher than the max set in Register 06.

    Charge voltage range is 3.5 V to 4.44 V with the offset of 3.5 V and steps of 20 mV (default 3.54 V), using bits B2-B7.  

    Charge current sense voltage offset is 37.4mV and default charge current is 550mA, if 68- mΩ sensing resistor is used and LOW_CHG=0.  With your higher resistance, the default charge current will be 68/82*550mA.  Using bits B2-B6 adds to the offset.  Datasheet page 37 has the example below:

    Regards,

    Jeff