This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ25125: BQ25125 BAT PIN and TS PIN double confirm schematic

Part Number: BQ25125

Dear,

We first time use BQ25125, could double confirm schematic as below chart:

If any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence.

  • Hello,

    You're missing a minimum of 1uF cap on BAT

    Please take a look at the following post.

    https://e2e.ti.com/support/power-management/f/196/t/826735

  • Hi, Raheem

    we will add 1uf cap on BAT and confirm check list.

    other question, If BQ25125 PMID pin connent to VINLS pin, have any concern?

    If any suggestion, Please advise me.

    Thanks,

    Best regards,

    Lawrence.

  • Hello,

    No concern with connecting VINLS to PMID. What are your RCOLD and RHOT values?

  • [Q&A]
    1. Waht voltage value of SW pin?
    2. Rcold/Rhot mean thermal resistor operate range?     
                                                       BQ2512X Schematic Checklist
     
    Minimum of 1uF capacitance on IN pin to GND. Account for capacitor derating. Ensure capacitor is rated to twice input voltage.
    >>Update. Add C221.
     
    Connect minimum 3uF capacitance on PMID pin to GND. Account for capacitor derating. Ensure capacitor is rated to twice input voltage.
    >>Update. Add C218 4.7u
     
    Ensure USBGND and PGND are tied together.
    >>OK! Checked.
     
    /CD pin is typically connected to MCU GPIO. Pin is internally pulled low with 900kΩ resistor. /CD is governed by table below.
    /CD State   VIN Absent      VIN Present
    Low    Hi-Z Mode       Charge Enabled
    High   Active BAT       Charge Disabled
    >>If no use this pin, can be floating?
     
    SDA pulled up VSYS with resistor
    >>Already pull high resistor close MCU side.
     
    SCL pulled up VSYS with resistor
    >>Already pull high resistor close MCU side.
    Connect appropriate resistor value to ILIM pin. The resistor value should be between 500Ω and 4kΩ.
    >>OK! Checked.
    LSCTRL should be pulled either high or low depending on desired startup state. LDO can be disabled or enabled through I2C regardless of LSCTRL state. If LDO voltage is updated through I2C, LDO will need to be disabled and then enabled for voltage change to occur.
    >>OK! Checked.
    Connect appropriate resistor value to ISET pin. The resistor value should be between 665Ω and 39.2kΩ.
    >>OK! Checked.
    Connect appropriate resistor value to IPRETERM pin. The resistor value should be between 549Ω and 15kΩ.
    >>OK! Checked.
    /INT is an open-drain status output that signals charging status and fault interrupts. Connect to an LED or pull up to VSYS (or external VIO) with 100KΩ resistor.
    >>OK! Checked.
    /PG is an open-drain status output that signals Power Good status. /MR can be level shifted to /PG when PGB_MR but in register 0x08h is enabled. Connect to an LED or pull up to SYS(or external VIO) with 100KΩ resistor. Can be left floating if unused.
    >>OK! Checked.
    /RESET is open drain active low in output. Pull up to VSYS (or external VIO) with 100kΩ resistor.
    >>OK! Checked.
     
    /MR is pushbutton input that can be used to reset the device or count for wake timers. This pin is pulled up internally and can be left floating if functionality is not needed. Note that if /MR is not used, the only way to exit shipmode if through VIN insertion.
    >>OK! Checked.
    Connect 2.2µH inductor to SW.
    >>OK! Checked.
    Connect minimum of 10µF capacitance on SYS. Account for capacitor derating. Ensure capacitor is rated for twice SYS voltage.
    >>OK! Checked.
    Connect minimum of 1µF to LS/LDO. Account for capacitor derating. Ensure capacitor is rated for twice LS/LDO voltage.
    >>OK! Checked.
    Connect minimum of 1µF from VINLS to GND. Account for capacitor derating. Ensure capacitor is rated for twice SYS voltage. VINLS is typically connected to PMID.
    >>OK! Checked.
    Connect minimum of 1µF from BAT to GND.  Account for capacitor derating. Ensure capacitor is rated for twice BAT voltage.
    >>OK! Checked.
    Follow datasheet procedure on TS pin. If TS will NOT be used, set the TS in off mode with RHI = 37kΩ and RLO = 50kΩ with NTC thermistor absent. RHI should be pulled up to VIN.
    >>OK! Checked.
  • SW is the switch node of the Buck converter. VSYS is the regulated output which should be at 1.8V after startup.

    Yes RCOLD and RHOT are the thermal resistor operation range you intend to use for you device.