• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 62 subscribers
  • Views 1191 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

bq24055evm - the battery will not reach the voltage regulation threshold (4.2V) or its full capacity which should be between 4.15 – 4.2V.

neguse gebremikael
Intellectual 800 points

In evaluation the EVM, I followed user’s guide (SLUU378-September 2009) document and data sheet (SLUS940B –SEPTEMBER 2009–REVISED JUNE 2012)

 

The device operate fine from either a USB port or AC adapter.

 For AC adapter, power supply set to 5V/800mA (Fast Charger)

  • RISET = 675 ohms
  • Termination Current set to 10% of Fast Charge ~80mA
  • Pre-Charge Current set to 5% ~160mA
  • RPRE-TERM = 2K ohms
  • The battery will not reach the voltage regulation threshold (4.2V) or its full capacity which should be between 4.15 – 4.2V.
  • The charger terminates charging LED-OFF when the battery output voltage is ~ 4.09V

 

Power supply set to 5V/540mA (programmed for (540mA at the factory)

 

  • RISET = 1000 ohms or 1K ohms
  • Termination Current set to 10% of Fast Charge ~54mA
  • Pre-Charge Current set to 5% ~108mA
  • RPRE-TERM = 2K ohms
  • The battery will not reach the voltage regulation threshold (4.2V) or its full capacity which should be between 4.15 – 4.2V.
  • The charger terminates charging LED-OFF when the battery output voltage is ~ 4.07V

 

Can someone please reply to the problems i am encountering?

  • 0
    TI__Guru*** 143870 points

    Where are you measuring the battery voltage, at the battery or on the EVM as close to the IC OUT pin as possible?

    What is the voltage on TS?  If too low, the TS pin may be forcing the IC into JEITA hot condition, which lowers the regulation voltage to 4.06V - 4.1V.  Figure 26 on d/s page 26 explains.

  • 0 in reply to Jeff F
    Intellectual 800 points

    I am measuring at J2 of the EVM. The voltage on TS pin is 0.15 – 0.16V.

  • 0 in reply to neguse gebremikael
    TI__Guru*** 143870 points

    V(TS) is outside the range of normal operation.  You either need to connect a 10k ohm resistor from TS ground to simulate a thermistor or connect a real 10k ohm thermistor to the TS pin.  With the EVM unpowered, you can install JMP5 and then turn potentiometer R8 until you measure 10kohm.  Datasheet figures 24 and 26 explain this functionality.

  • 0 in reply to Jeff F
    Intellectual 800 points

    I added 10k ohms resistor from TS to ground. While the battery is charging input current ~ 300mA, I am getting voltage on TS pin about 0.18V, is this correct?  It seems to me the voltage I am reading on TS pin does not follow figure 26 of the data sheet operation.

  • 0 in reply to neguse gebremikael
    TI__Guru*** 143870 points

    If JMP5 shunt is removed and you add a 10k resistor from TS to GND, the voltage should not be 0.18V.  Alternatively, you can remove the 10k resistor, replace JMP5 shunt and adjust the potentiometer until the resistances on TS is 10k or the TS voltage is between ~300mV and 750mV.  I assuming that a battery or battery simulator is attached to OUT.

  • 0 in reply to Jeff F
    Intellectual 800 points

    This is regarding BQ24055 IC:

    For processor or host monitoring, the processor’s power rail is 3.3V VCC. I need to monitor the CHG and PG pins.  What values should I use for pull-up resistors?  I need to monitor when the battery is fully charged, change in STATUS.

    • Between the processor’s power rail and CHG pin?
    • Between the processor’s power rail and PG pin?

    I am using STM32L151VBT6 MCU.

    I used 3.3K and 4.7K resistor values for pull-up; however I do not see change in STATUS. The charger CHG LED remains on and no change in STATUS on MCU display. This is on a fully charged battery.

  • 0 in reply to neguse gebremikael
    Intellectual 800 points

    [View:http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/179/1778.Li_2D00_Ion-Charger-Rev03.pdf

    Please see attached schematic.