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BQ21040: BQ21040

Kapil Kesharvani
Prodigy 30 points
Part Number: BQ21040

Hi,
I am Kapil.

I am working on battery Charger BQ21040DBVR.
When I am connecting the Li- ion battery at the output pin and TS pin I am getting the power in the remaining
portion of the schematic from Battery Charger IC. But When I am connecting the power to the input of battery charger 5V - 1.0A, I am not getting the power to the remaining part of the circuit from output terminal of battery charger IC.
I choose below values.
Cin= 1.0uF/16V
Cout= 2.2uF/16V
Riset= 5.1K --- output current is 100mA
Rts= 10K- not connecting thermal pin
Rchg= 1.5k + LED

Can somebody help me to resolve this issue.

  • 0
    Prodigy 30 points

    Hi,

    In the last post, I described the values of passive elements in BQ21040 IC. I am taking the power from battery charger IC to Bluetooth module NRF52832. But the problem is that I am not getting sufficient power from battery charger IC to Bluetooth module to drive.
    I am also confused for Pin TS. In my battery, there is no thermal pin so I connected 10K resistor in the TS pin to ground parallel with Battery pin.
    In the datasheet, it is given that if NTC sensing is not needed, connect this terminal to VSS through an external 10 kΩ resistor. A 250kΩ from TS to
    ground will prevent IC entering TTDM mode when the battery with the thermistor is removed.

    I don't understand the function of 250K.

    Can someone help to solve this problem?

    Thanks in Advance.

    Regards 

    Kapil

  • 0 in reply to Kapil Kesharvani
    TI__Expert 3350 points

    Hello Kapil,

    I hope this helps.

  • 0 in reply to David C
    Prodigy 30 points

    Hi David,

    Thanks for the response. 

    I went through that part that you shared. But I want to know what value of the resistor should I need to keep for TS pin? 

    Please tell me if I wrong. In my battery, there is no thermal pin so I kept 10 K resistor with TS pin and connected to the ground. The Battery is connected with out and TS pin.

    Please let me know if i am missing something.

    Please share your email id I will share the schematic with you.

    Regards,

    Kapil

  • 0
    TI__Expert 3350 points

    Hello Kapil,

    If you are using a battery with no internal thermistor and will not be using a thermistor at all, connect a 10k resistor from the TS pin to ground.

    Your battery should be connected from Vout to GND.

    Regards,

    David