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BQ25155: input supply current in power up

Toshiro Imi
Expert 7170 points
Part Number: BQ25155
Other Parts Discussed in Thread: BQ25150

Hello,

Our customer has a question about input supply current information during BQ25155 power up. While I checked in the datasheet, I realized BQ25155 passes though 3 states until start charging.

Could you please check the file and let us know if my understasnding is correct ?

Could you please also let us know the supply input current for each state IIN(1), IIN(2), IIN(3) ?

Best regards,

BQ25155 IIN estimation.pdf 

  • 0
    TI__Genius 17545 points

    Hi Toshiro,

    I'll look into these currents and let you know my findings.

    Best Regards.

  • 0 in reply to Juan Ospina
    TI__Genius 17545 points

    Hi Toshiro,

    For IIN1 input current this is somewhat dependent on VIN voltage but it can range from 10 - 60 uA quiescent current.

    For IIN2 input current this input current is an average of about 500 uA

    For IIN3 input current is about 780 uA but PMID won't rise until VIN > VINDPM so I believe IIN3 doesn't really exist.

    Best Regards.

  • 0 in reply to Juan Ospina
    TI__Expert 7170 points

    Hi Juan,

    Thank you very much for telling me the supply current information.

    I have revised and out the number in below. please let me know if my understanding is incorrect.

    By the way, I am curious that the PMID power up timing since the datasheet "9.4.5 Power-Up/Down Sequencing" is discribing as "If VIN > VBAT + VSLP and VIN < VOVP, PMID will be powered by VIN and if VIN > VIN_DPM charging will start if enabled.". So I would beleiaved PMID power up in VIN > VIN+VSLP.

    Best regards,

    BQ25155 IIN estimation_2.pdf

  • 0 in reply to Toshiro Imi
    TI__Genius 17545 points

    Hi Toshiro,

    It looks like I was a bit confused as I was using a BQ25150 for this experiment. The BQ25150 has different startup settings than the BQ25155, particularly VINDPM. VINDPM is disabled by default on the BQ25155, so effectively VIN > VBAT + SLP and VIN < VOVP will be sufficient for VIN to power PMID. Sorry for the confusion, your original understanding was correct.

    For the BQ25150, If VIN > SLP and VIN < VOVP then PMID will look to draw power from VIN. However if VIN < VIN_DPM the input current will be limited preventing VIN from charging the PMID capacitor. If VBAT is present then the battery will supplement to keep PMID high, but if there isn't one present then VIN will have to exceed the VINDPM limit for PMID to go high. 

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    TI__Expert 7170 points

    Hi Juan,

    Thank you for your the deatil. I understood that VINDPM will impact to the power up sequencing. Because BA25155 does not enable in default, I understand sequencing on the attchment is correct. Please let me know, if my understanding is incorrect.

    BQ25155 IIN estimation_3.pdf

  • 0 in reply to Toshiro Imi
    TI__Genius 17545 points

    Hi Toshiro,

    Yes this is correct. It is important to note that PMID will only be the same voltage as VIN as long as VIN is below the PMID regulation voltage.

    Best Regards.

  • 0 in reply to Juan Ospina
    TI__Expert 7170 points

    Hi Juan,

    Thank you very much. I understood.

    Best regards,