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BQ24075: BQ24075 operating tolerance on higher temperature environment

Leo Chow
Expert 3120 points
Part Number: BQ24075

Hi,

My customer is in midst of qualify their end equipment with Safety Committee for BQ24075 & they have queries on parameters mentioned below. Please advise. Thanks.

 

1) At pin12 and pin16 (ILIM and ISET) of BQ24075, will there be a potential of ILIM and ISET value change across the temperature (low=0degC, roomtemp=25degC and high=45dgC)? If yes, can you advise on the tolerance of each targeted temperature? in our use case we're setting resistor value to meet our desired charging current.

2) For Rilim and Riset calculation stated in the datasheet, is it based on the nominal temperature (~25degC)? Is there any calculation on these two value at extreme temperature? Our end equipment may be required to operate on higher dynamic temperature environment such as winter & high summer.

 

Regards,

Leo

  • 0
    TI__Mastermind 21590 points

    Hello Leo,

    1) The tolerance for ILIM and ISET are show in the KILIM and KISET parameters. For KISET, the minimum charge current factor is 797 and the maximum is 975. KILIM is shown below depending on the charge current range. This is for 0C to 125C.

    2) For calculating RILIM and RISET at ~25C, use the typical values from the datasheet. For extreme temperatures, i'll suggest the value that gives the lowest current which will be the max values from the datasheet so charging current doesn't exceed expected limits. For example, if you don't want the charge current to exceed 1A even at high temperatures, use KISET = 975 though you might have lower current at room temperature.

  • 0
    Prodigy 10 points
    Thanks for your previous feedback. We are still in line with safety review and few concerns being brought up by the committee.

    We are using ~1Amp input and output current for charging, hence will there be any safety related fault (eg: electrical shock, smoke, burnt, etc) to the circuit if the IN Pin and BAT1/BAT2 Pin shorted to their adjacent pin?

    ..........................................................................................
    High Current Pin Adjacent Pin
    IN = Pin13 TMR = Pin14
    ILIM = Pin12
    ..........................................................................................
    BAT1/BAT2 TS = Pin1
    CE = Pin4 (connected to GND)
    ..........................................................................................

    I appreciated if you can share the knowledge.
  • 0 in reply to Noor Asmadi Amir
    TI__Mastermind 21590 points
    Hello Noor,
    while i can't make any guarantees with regards to safety tests done by customers, shorting VBAT to ILIM will stop the device from charging. Shorting the TS pin to BAT will cross the temperature threshold and stop charging due to a "TS" fault. Shorting BAT to CE while CE is shorted to GND will cause issues because the battery will be shorted.