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BQ2057C: BQ2057C little charge current

Star Xu
Genius 9645 points
Part Number: BQ2057C

Hi

 My customer use BQ2057C to charge battery. The current sense is 0.1 ohm, transistor is FZT788B, the actual charging current is only about 200mA in the case of 5V voltage, and can rise to more than 400 mA when it reaches above 5.4v, how should I modify the circuit?

Thanks

Star

  • 0
    TI__Guru* 75656 points

    Hello Star

    I suspect the problems is due to input voltage drop reducing the 5V and degrading operation of the unit, VCC min in 4.5V.  Try testing with higher input voltage and check the VCC voltage. 

    Also this is a very old device with external sense resistor and mosfet -- recommend looking at the BQ2400X or BQ2404X family of devices.