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Original question:

BQ24079: What is Vin(low) value or Vin(low) loop?

BQ24079: Vin lower than min value causes lower CV or lower charging rate for battery?

Prithvi Raj Narendra1
Intellectual 550 points
Part Number: BQ24079
Other Parts Discussed in Thread: BQ25170

Hello,

We are looking to use BQ24079 as a charging solution for a single Li-Ion battery. In our solution because of other constraints have only a 4.2V source as Input source for the charger. This is less than the min input operating range value of 4.35V. How would this affect the charging of the battery?

Would this cause longer time for charging to 4.1V since the dropout voltage reduces with output current? This is with say 20 mA termination current.

Or would it be such that the CV for the battery would occur at a lower voltage than 4.1 V?

Thanks, Prithvi

  • +1
    TI__Expert 8245 points

    Hi Prithvi,

    I tested this behavior in the lab and was not able to observe any charge current when VIN = 4.2V. Once VIN > 4.35V the charge current begins to rise until it reaches its expected value when VIN = 4.58V. I used 500mA ICHG for this test.

    This being said, I dont think the BQ24079 will work for your application as no charge current was observed at 4.2V VIN.

    Have you looked at the BQ25170? I would recommend this IC for your application.

    Best Regards,

    Jackson