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BQ24105-Q1: About tCHARGE

Part Number: BQ24105-Q1

Hi TI-team

My customer have a question.

The maximum time that can be set in the data sheet is described as 572minutes (9.533 hours).

In "Charging NiMH Battery Using bq24105-Q1 in Automotive Applications", it is described as "It is verified on the bench that the timer can be up to 20 hours."(P.4).

Which is correct ?

Is it safe to assume that if it is used for less than 20 hours, it will not be a problem ?

 

Best Regards,

Koji Hayashi

  • Dear Koji,

    Please refer to Section 2 of the application note. It states, "The first case is when the battery open circuit voltage is below 1.24 V/cell, charge is enabled along with safety timer. Once safety timer is expired, the charging is terminated. Then battery open circuit voltage is checked again, if at this time the voltage is below 1.34 V/cell, then the charge is re-enabled and timer reset."

    In order to clear the timer fault, the /CE pin has to be toggled. Please note that a micro-controller is needed in order to make the charging procedure described in this application note possible.

    Thanks,

    Mike Emanuel

    Please click "This resolved my issue" button if this post answers your question.

  • Hi Mike-san

    Thank you for quick response.

    Without MCU: 572 minutes (9.533 hours) in data sheet.

    With MCU: 16 hours (20 hours in the bench) at a 0.05C rate.

    Do you agree with the above recognition ?

     

    Best Regards,

    Koji Hayashi

  • Koji-san,

    Without a microcontroller the charge timer has a maximum of 572 minutes.

    With a microcontroller, the charging scheme in the application note has been verified on the bench up to 20 hours.

    Thanks,

    Mike Emanuel 

    Please click "This resolved my issue" button if this post answers your question.