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Original question:

BQ2000 Issue at Charge Done

BQ2000: BQ2000 Issue at Charge Done

Kami Huang60
Genius 3830 points
Part Number: BQ2000

Dear Sir/Ms.

There are two questions I would like to ask.
1: Modify RC charging time
About 9 hours (540 minutes)
Reference formula
MTO = R* C* 35,988
C is 0.15UF
R=100K
But the actual measurement became 17 hours.
Can I have suggested R. and C values?
2: Will the following circuit
   The role of CHEMISTRY....
   It seems that if FLOATING is FOR Li-ion
                          Connected to BAT- is FOR NiCd/NiMH....
   Because it seems that the customer is entering Li-ion, so the time becomes 2 times MTO.

If you need schematics,  I can ask for it from the customer.

Best Regards,

Kami Huang

  • 0
    TI__Guru 56650 points

    Kami,

    Sorry for the delay.

    The BQ2000 can charge both Li-ion battery and NiMH battery.

    If VBAT cannot reach the charge voltage setting (the voltage on the BAT pin rises to the internal VMCV reference) before the safety timer kicking in, the charger circuit provide a constant charging current until other termination condition is triggered. That is good for a NiMH battery.

    If VBAT can reach the charge voltage setting before the safety time kicking in, the charger provides constant current charge first, and then constant voltage charge. This is good for a Li-ion battery.

    In your case, short "Chemistry" to "BAT-" can make "BAT" get a lower feedback voltage and VBAT cannot reach the charge voltage setting. That is why "Connected to BAT- is FOR NiCd/NiMH...."

    I agree "the customer is entering Li-ion, so the time becomes 2 times MTO"