Electrical – Li-Ion charger IC leakage current confusion

chargerdischargeleakage-currentlithium ion

I'm currently building a Li-Ion battery charging circuit which has a 5V/2A input. It should implement load-sharing in order to keep the output alive during charging.

For charging, I found the BQ25606 IC from Texas Instruments and it seems to fulfill all of my requirements. However, one aspect confuses me when looking at the datasheet. It states "58-μA Low Battery Leakage Current with System Voltage Standby". The leakage current is only mentioned at the front page and I've had a hard time thinking of what it might refer to.

Does that mean that when the charging cycle is terminated a continuous current flow of 58μA slowly discharges the battery? The Li-Ion battery I want to use discharges less than 5% per month. Do these two discharging processes add up? Or am I totally mistaken and the 58μA refer to something completely different?

Best Answer

Yes and no. That is the quiescent current when there is no power supply. Page 7 of the datasheet says 5uA max when Vbus exists (charge terminated, charger still connected to power). 85uA (58uA typical) is when there is no power to the charger.

58uA drain on a fully charged 2000mAh battery would deplete it to 20% in 27586 hours, or 3 years.... to put this in context.

And yes, it is in addition to the battery self drain.