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BQ25606: Battery Charger profile

Eric Chen4
Expert 2370 points
Part Number: BQ25606
Other Parts Discussed in Thread: BQ25600

Hi,

May I know what is BQ25606 Battery Charger profile?

Thanks.

Best Regards,

Eric

  • 0
    TI__Prodigy 150 points

    Hi Eric,

    The bq25606 uses the constant current/constant voltage (CC/CV) charging cycle.

    When VBAT < VSHORT, then the battery is charged with the short circuit current, ISHORT, which is typically 90mA. This tests if there is a short inside the battery. 

    When VSHORT < VBAT < VBATUVLOW, the battery is charged with the precharge current, IPRECHG, which is about 5% of ICHG.

    When VBATUVLOW < VBAT < VBATREG, then the battery is charged with ICHG, which is set by the resistor on the ICHG pin.

    When VBAT reaches VBATREG, the battery is charged at a constant voltage of VBATREG, and the charge current decreases until it drops below the termination current, ITERM, which is about 5% of ICHG. When the charging current below the termination current, then charging is terminated.

    Although it is not in the BQ25606 datasheet, a graph of the charging profile can be found in the BQ25600 datasheeet on page 23. See here.

    I hope this helps!

    Bill

  • 0 in reply to Bill Schepers
    Expert 2370 points

    Hi Bill,

    Thanks you help.

    I already check BQ25600 battery Charger Profile but I have one questionas below.

    At BQ25600 battery profile, the Regulation Voltage is 3.5V to 4.4V and is it the same with BQ25606?

    Or the Regulation Volatge of BQ25606 is 4.1V~4.4V base on Rvset define as below, right?

    Now we use 2000mAh Li-ion battery and need charger done within 2hr.

    If using BQ25606 EVM, how can we workaround it?

    Please kindly provide your suggestion for our reference.

    Thanks.

     

  • 0 in reply to Eric Chen4
    Expert 2370 points

    Hi Bill,

    Thanks you help.

    I already check BQ25600 battery Charger Profile but I have one questionas below.

    At BQ25600 battery profile, the Regulation Voltage is 3.5V to 4.4V and is it the same with BQ25606?

    Or the Regulation Volatge of BQ25606 is 4.1V~4.4V base on Rvset define as below, right?

    Now we use 2000mAh Li-ion battery and need charger done within 2hr.

    If using BQ25606 EVM, how can we workaround it?

    Please kindly provide your suggestion for our reference.

    Thanks.

    Eric

  • 0 in reply to Bill Schepers
    Prodigy 90 points
    Hi Bill
    I have a problem of the charger profile in the datasheet. I want to know why does the charging current fall down when the Vbat up to Vbatreg?
    I have one idea that the internal buck circuit makes Vsys drop to make the Vds of Q4 MOSFet drop.
    Do youv agree with me?
    I want to know your explannation.

    Thanks for your reply.

    Xuehao
  • 0 in reply to Eric Chen4
    TI__Prodigy 150 points

    Hi Eric,

    The regulation voltage for the BQ25600 has a range of 3.856V - 4.624V. 

    The regulation voltage for the BQ25606 is what you see in the table from the datasheet, where VBATREG can be set to 4.208V, 4.352V, and 4.4V. What regulation voltage do you need for your battery?

    With the BQ25606 and a 2A charge current (assuming you are charging at 1C), the battery may be done charging within 2 hours. The charge time is dependent on your battery and the impedance between the battery and the BAT pin on the chip.

    I hope this helps! 

    Bill

  • 0 in reply to xuehao yin
    TI__Prodigy 150 points

    Hi Xuehao,

    When the charger charges at constant voltage (CV), the charge current is dictated by the cell voltage, cell impedance, and line impedance. As the charger charges in CV, the cell voltage increases and the cell impedance decreases. Because the cell voltage increases, and the voltage between the BAT pin and the cell decreases, the charge current is reduced. 

    I hope this helps!

    Bill

  • 0 in reply to Bill Schepers
    Prodigy 90 points
    Hi Bill,

    Thanks for your reply! your answer is very nice!

    Xuehao
  • 0 in reply to Bill Schepers
    Expert 2370 points
    Hi Bill,
    Thanks your support and may I have your E-mail then need your help to review BQ25606 schematic first?
    Thanks.

    Eric
  • 0 in reply to Eric Chen4
    TI__Mastermind 25800 points

    Hey Eric,

    You can go ahead and send your schematic to joelh@ti.com and I can review the schematic for you.

    Regards,

    Joel H