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BQ2057W: Leakage Current is too HIGH

Hong Tam Le
Prodigy 120 points
Part Number: BQ2057W

Hi.

I design a charger batteries board. I use 2 cell batteries 18650 3.7V@3.400mAh.

Charging is Ok. But when I remove adapter +9V, always have a leakage current 4mA to BQ2057W circuit from batteries (VBAT). It makes the remain capacity of batteries go down so fast.

Could you help me fix my circuit?

Thanks.

Tam.   

  • 0
    TI__Guru* 75746 points
    Hello
    I checked the EVM and leakage with no input is about 50uA.
    Would recommend comparing the EVM circuit with your design, they use a similar pass transistor configuration.

    The voltage divider R208 and R209 are not needed, battery can be connected directly to BAT pin. Lower resistor R209 will cause leakage current.
  • 0 in reply to Bill Johns
    Prodigy 120 points
    Hi Bill Johns.
    Thanks for your support. I found out my mistake that make high leakage current on charger circuit.
    The reason is at the voltage divider R172 & R173. The value of R172 and R173 are too small so the leakage current is so high.
    I changed value of R172 & R173 to 1.5 MOhm. Now the leakage current is about 50-60 uA,
    Again, thanks for your support quickly.
    Tam.