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BQ24130: I2C control using digital potentiometers

Emmanuel Roble
Intellectual 405 points
Part Number: BQ24130
Other Parts Discussed in Thread: TPL0102-100, , BQ24765, BQ24640

Hi,

I would like to verify if BQ24130 can be digitally controlled using digital potentiometer like TPL0102-100.

  • 0
    TI__Guru*** 146695 points

    Hi Emmanuel,

    The host/I2C controllable aspects of the BQ24130 were intended to be Q3/Q4/Q6 turn on/off, CMOD high/low and ISET1 pull down for disable.  If your question is whether the ISET1 and/or ISET2 resistors can be replaced with digital potentiometers, then yes, in theory, potentiometers should work to dynamically change the precharge/charge current, however, we have not tested such a configuration.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Intellectual 405 points

    Hi Jeff,

    No I intend to have the charge and pre-charge current fixed and Dynamically change voltage by placing the digital potentiometer to the BAT pin as feedback. I would like to verify also what digital potentiometer bandwidth is need to accomplish this.

    Regards,

    Emman

  • 0 in reply to Emmanuel Roble
    TI__Guru*** 146695 points

    Hi Emman,

    In theory, using a potentiometer as a feedback resistor should work as well but we have not tested.  I am not familiar with "bandwidth" as a pot spec.  Is that referring to how fast you can change the pot's resistance?  If so, I would suggest not changing any faster than the loop response which is ~1ms.

    Regards,

    Jeff 

  • 0
    Intellectual 405 points

    Hi Jeff,

    I would like to verify also if I will have problems charging supercapacitors with BQ24765

    Thanks,

    Emman

  • 0 in reply to Emmanuel Roble
    TI__Guru*** 146695 points

    Emman,

    A LiIon battery charger can successfully charge supercapacitors, assuming the BATREG voltage can be adjusted to the match the supercapacitor voltage.  However, most battery chargers have either a short-circuit voltage or pre-charge voltage threshold or both.  Below the voltage thresholds the charge current is significantly reduced. This results in very long charge times.  The standalone BQ24640, modified for super cap charger, skips precharge.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    TI__Guru*** 146695 points

    Hi Emman,

    I haven't heard from you in a while so I am going to close this thread.  You will have a few days from now to continue to post but in a week or so this thread will lock.  After that you will need to post a new thread for additional questions.

    Regards,

    Jeff