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BQ2002: Can this device CC current down to 10mA?

Part Number: BQ2002
Other Parts Discussed in Thread: BQ25172

Hi team,

My customer would like to design BQ2002 because of some reason.

The battery material is NIMH  and max working voltage around 1.52V. 1cell design only.

And the question is they need very low CC current in application. 

So please advise can we program CC=10mA value?

Thanks

  • Hello

    The problem with 10mA may be detection of charge complete condition, -dV or dT at this low a charge current.

    What is the cell capacity?

  • Bill,

    Capacity is 20mAh.

    Thanks

  • Hello 

    If the battery capacity of 20mAh and charge current of 10mA should work. This is 50% of capacity and can detect the -dV or dT.

    Has customer looked at our new device the BQ25172?  Does not have fast charge option, based on timer but may work for application.

  • Bill,

    BQ25171 is used before but it is fail in customer's specification. And that's why we are thinking BQ2002 may be choice?

    I think you should be in email loop, the email subject is RE: [EXTERNAL] RE: NiMH charger BQ25171 questions

    And BTW, can BQ2002 can program CC current lower to 5mA as well?

    Thanks

    As our NiMH battery max working voltage around 1.52V, we add a resistor, 20 ohm between charger, BQ25171 and NiMH battery. Based on charging current = 10mA and timer = 4 hours, the charger stops charge at OVP voltage = 1.7V shared by 20 ohm = 0.2V and battery = 1.5V after charging the battery for 1.5 hours.

     Thus, using 6 hours timer setting doesn’t let the battery be charged more power  capacity as the charging process can finish in 1.5 hours.  As we discuss over the phone, whether you can modify charging current 10mA (min charging current in the spec) to 5mA for more complete full charging over 6 hours or other ideas.  This way will support 8 ~ 9 hours use time for the TWS earbud. Thanks.

  • Hi Paul

    And BTW, can BQ2002 can program CC current lower to 5mA as well?

    The BQ2002 will control (ON/OFF) an external current source using the CC pin, does not have a current regulator.  5mA is possible but this is an external circuit under control of the CC pin. 

    BQ2002 will monitor voltage and temp to determine charge termination.