BQ51050B: LiPo 3.7V charging

Part Number: BQ51050B

I want to charge a small LiPo battery of 3,7V. Can it be charged with the BQ51050B component? 

As I can see, the output voltage options are around 4,2V.

1 - How the component can notice that the battery is completely charged at 3,7V?

2 - How the component will stop charging the battery?

3 - How the charging ending can be notified? I see that CHG can do that, but as long as I have test it, CHG is always high (both charging or not)

I am measuring the currents with an INA219 between the battery and the BQ51050B. Using the 3,7V battery, I checked that it was charged to 4,096V. Afterwards, it started decreasing the voltage in a constant negative current of -70mA (consuming from the battery). Which could be the reason for that?

Thank you so much in advance,

Gerardo

1 Reply

  • Hello
    1 - How the component can notice that the battery is completely charged at 3,7V?---If you have a LiPo battery it it will probably be charged to 4.2V, check battery manufactures recommendations. Charge is terminated based on charge termination current, see date sheet section 8.3.3

    2 - How the component will stop charging the battery?--During the Taper phase of charging current will decrease to termination current.

    3 - How the charging ending can be notified? I see that CHG can do that, but as long as I have test it, CHG is always high (both charging or not)---Use the CHG pin, it will indicated charge complete.

    Adding resistance between charger and battery will cause sense voltage at BAT to change can cause problems, current sense resistor for INA219 may be an issue.
    Charging current can be monitored at the ILIM pin, this voltage is proportional to charge current.

    Best Regards,

    Bill Johns,  Applications Engineer

    Texas Instruments Inc

    Dallas, Texas

    Please click "This resolved my issue" button if this post answers your question.