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BQ25895: Schematic review

Ollie Killean
Prodigy 10 points
Part Number: BQ25895

Tool/software:

Hi folks.

Would I be able to get a quick review on this schematic for the BQ25895?

My requirements:

  • Input is via USB-C, so VBUS would be powered at 5 V from 500 mA and above.
  • Power draw on VCC will never exceed 600 mA.
  • USB OTG must be disabled and will not be used in the future.
  • Battery charging must be enabled, unless disabled by the microcontroller by pulling PWR_CE high.
  • I calculate that the 330 Ω resistor between ILIM and GND will limit charging current to the battery to between 0.96 - 1.18 A (around 1.07 A typical). To confirm, am I correct?

Many thanks!

  • +1
    TI__Mastermind 31570 points

    Hi Ollie, 

    Thank you for reaching out via E2E. Please see my comments below. 

    I have reviewed you schematic and all looks good. All necessary components are included. 

    Ollie Killean said:
    USB OTG must be disabled and will not be used in the future.

    OTG pin connected to ground will ensure OTG mode is always disabled. 

    Ollie Killean said:
    Battery charging must be enabled, unless disabled by the microcontroller by pulling PWR_CE high.

    With /CE pin pulled low charging is enabled by default. Please be aware charge can also be disabled via I2C.

    Ollie Killean said:
    I calculate that the 330 Ω resistor between ILIM and GND will limit charging current to the battery to between 0.96 - 1.18 A (around 1.07 A typical). To confirm, am I correct?

    Yes Rilim = 330 Ω will set input current limit to typical 1.07A. Please be aware the 1.07A input current limit applies to both charging and powering VCC. With input current limited to approx. 1.07A if VCC draws 600mA the battery will charge at a current less than 1.07A. 

    Best Regards,

    Garrett

  • 0 in reply to Garrett Kreger
    Prodigy 10 points

    Hi Garrett.

    Thanks for your response.

    Garrett Kreger said:
    Yes Rilim = 330 Ω will set input current limit to typical 1.07A. Please be aware the 1.07A input current limit applies to both charging and powering VCC. With input current limited to approx. 1.07A if VCC draws 600mA the battery will charge at a current less than 1.07A. 

    I somehow wasn't aware that ILIM limited the input instead of charge current (which to be honest, makes quite a lot of sense 'Input LIMit'!). I will adjust the resistor value appropriately.

    Good evening.

    Ollie