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BQ24038: What is the best solution in this customer case

user5013697
Intellectual 490 points
Part Number: BQ24038
Other Parts Discussed in Thread: BQ25606

Hello

Please see attached file.

My customer is designing the battery charger cradle and ask us to sggest the lowest chager IC.

please tell us any advice which Charger IC sould I suggest tothem?

waht is the best solution?

Best regards

YamaneCustomer Application.pptx

  • 0
    TI__Prodigy 640 points
    Hello Yamane,

    bq24038 is a good selection, as it can have battery charge voltage of 4.36 and max charge current of 1.5A

    The only other linear charger that offers Vbat of 4.36 is bq2401x, which has max charge current of 1A.
  • 0 in reply to Diana Bodenmiller
    Intellectual 490 points

    Hello Diana

    Can BQ24038 correspond to 1.5A charge curent?

    how is the Ron resistance of Q1 and Q2?

    I think the Q1 Ron range is approximately 300 mohm, if it is so, it a few designe margin.

    Sould I propose switching chager IC to customer in this case?

    Best regard

    Yamane

  • 0 in reply to user5013697
    TI__Mastermind 21590 points

    Hi,

    Yes, the maximum charge current is 1.5A. The drop out voltage for both Q1 and Q2 are highlighted below. Linear chargers are typically suggested for charging current below 1.5A. Switching chargers tend to have higher BOM and much bigger due to the need for inductors.  Switching noise is must also be considered. i'll suggest going with the linear charger depending on the requirements of the customer.

    Regards,

    Raheem

  • 0 in reply to Raheem
    Intellectual 490 points

    Raheem

    Thank you for your reply, but I have concern about charge current (1.5A charge).

    Please see attached file and could you please reply your opinion.

    If my view is not correct, please explain why I'm misunderstanding.

    please your help.

    Best regards

    YamaneBQ24038_question.pptx

  • 0 in reply to user5013697
    TI__Mastermind 21590 points

    Yamane,

    The IC has thermal regulation which reduces the charge current when the temperature gets outside certain thresholds looking at the voltage on the TS pin. This shouldn't be a concern.

    Regards,

    Raheem

  • 0 in reply to Raheem
    Intellectual 490 points

    Hello Raheem

    Thank youfor your reply.

    you mention about thermal protection and BQ24038 restricts charge current besed on junction temperature.

    as a result, is that meam BQ24038 cannot charge the battery with 1.5A when Low battery voltage ?

    I think swiching chager is more better in this customer case.

    I would like to suggest to the cutomer with BQ25606, but EVM is not available at TI store.

    what is the alternative solution?

    Best regard

    Yamane 

     

  • 0 in reply to user5013697
    TI__Mastermind 21590 points
    Yamane,
    Sorry about the confusion. The BQ24038 uses the TS pin is used to monitor the battery temperature to ensure it stays within safe limits. The IC also has thermal regulation that reduces the current when the junction temperature is higher than Tj(REG) due to the power dissipation. As you stated, the power dissipation is high for only a certain part of the charge cycle. The current is reduced when this happens. When the power dissipation reduces as the battery voltage increases, the charging current increases back to the one set by the customer.
    Regards,
    Raheem