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BQ25306: remote sense for 4.4V/3A battery

Ann_Lien
Genius 10640 points
Part Number: BQ25306
Other Parts Discussed in Thread: BQ25790

Hello expert,

My customer has one request ford charger and need to find solution to support 4.4V/3A charging voltage and current. They also need remote sense for voltage sense since they have trace loss between battery connector to charger. May we know if we have suitable solution could provide to customer? Thanks a lot!

Best regards,

Ann Lien

  • 0
    TI__Mastermind 24075 points

    Hi Ann,

        BQ25306 is a good candidate. The BAT pin is to be tied directly to the battery for remote sensing, so that true battery voltage is sensed, ignoring the trace loss, and increasing time spent in CC for faster charging. As it has a resistor divider to set charge regulation voltage, it can support battery voltage from 3.4V up to 9V setting, and can also charge at 3A. See the link here: www.ti.com/.../BQ25306EVM

  • 0 in reply to Kedar Manishankar
    TI__Genius 10640 points

    Hello Kedar,

    May I know if this is not real remote sense like BQLEGO which has BATP/BATN? Thanks!

    Best regards,

    Ann Lien

  • 0 in reply to Ann_Lien
    TI__Genius 10640 points

    Hello Kedar,

    Let me double check again. We can use BAT/FB_GND to implement remote sense to reduce IR loss. Am I right? Thanks a lot!

    Best regards,

    Ann Lien

  • 0 in reply to Ann_Lien
    TI__Mastermind 24075 points

    Hi Ann,

       This is real remote sensing and is same as BQ25790. In BQ25790 it has powerpath, so there is a power BAT pin (BATFET connected between SYS and BAT), and also a remote BATP sense pin. BQ25306 is non powerpath device so there is no need for power BAT pin, as battery would just be connected at output of inductor and output capacitor that is connected at SW. So in this part the BAT pin is the remote battery sense pin.

    Yes, using the remote BAT pin to tie directly to sense real battery voltage, will ignore IR drop across wire and trace impedance between battery and where charger senses battery voltage, which will increase time in CC and shorten battery charge time.

    FB_GND reduces battery leakage current considerably due to external resistor divider.

  • 0 in reply to Kedar Manishankar
    TI__Genius 10640 points

    Hello Kedar,

    Got it and thanks for your detail explanation :)

    Best regards.

    Ann Lien