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BQ24172: minimum termination current at 20m-ohm

PAN-M
Mastermind 8375 points
Part Number: BQ24172

Dear Team,

KTERM is 10% of Fast Charge current, but is written as "The minimum current is 120 mA on 10-mΩ sense resistor" in a note.
In the case of 20m Ω, how much is the minimum current? 120mA?
Does Termination current unstable when I set Fast charge current to 700mA? (20m-ohm)

Regards,
PAN-M

  • 0
    Mastermind 8375 points

    What percentage error is Termination current when I set Fast charge current to 700mA?
    70mA+- xx%?

  • 0 in reply to PAN-M
    TI__Genius 10385 points

    PAN-M,

    In the case of 20m Ω, how much is the minimum current? 120mA?

    As described in section 9.3.2 of the datasheet V_ISET must be at least 120mV to enable charging, so by using equation 2 we can find the minimum value for I_CHARGE. I have calculated it to be 300mA.


    Does Termination current unstable when I set Fast charge current to 700mA?

    By Ohm's law your V_SRP-SRN in termination would be 1.4mV. This is a pretty small voltage drop so your termination current regulation accuracy would be greater the +/-40%. If this is not suitable for your application, then you will need a larger sense resistor. 


    I hope this helps resolve your issue,

    Ricardo