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BQ25890: VSYS load regulation without battery

Shota Mago
Expert 8110 points
Part Number: BQ25890

Hi team,

I'm an FAE supporting some industrial companies.

My customer is considering using BQ25890 so that it can be used with a certain load in the case of w/o a battery.

Specifically, he considers current of VSYS to be 3.5A or so.

Then, he provided 3 questions as follows

  1. Regarding Fig.5, is this battery chargeable condition(CHG_CONFIG=Enable and CE_=LO)?
  2. Could you please provide the data of VSYS load regulation when increasing the VSYS w/o battery?
  3. Just for making sure understanding
    In terms of Fig.6, since VBAT is 4.2V, it means charging is nearly compete and it's almost supplied to the SYS side.
    Is this correct?

I'm looking forward to hearing back from you.

Best regards,

Shota Mago

  • 0
    TI__Guru**** 166136 points

    Shato,

    Regarding 1, yes, charging was enabled but the curve would look like same if a resistive load was on SYS since VBAT=2.9V < SYSMIN=3.5V.

    Regarding 2, with charging disabled, VSYS=SYSMIN+150mV typical where SYSMIN can be adjusted from 3.0V to 3.7V.  The profile will be similar to that shown in Figure for SYSMIN=3.5V for the other SYSMIN voltages. 

    Regarding 3, in figure 6, VBAT>SYSMIN because the battery is at full charge so VSYS = VBAT+50mV typical.  The Q4 BATFET is fully on for ISYS>0.5A.