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BQ25710: Counter plan for ISL9241 (Hybrid Power Buck-Boost)

Satoshi
Guru 19645 points
Part Number: BQ25710

When the condition of high current on 4-cell buck-boost charger, ISL9241 is higher efficiency than bq25710.

I think that Hybrid Power Buck-Boost (HPBB) is matched high current condition.

Is there any idea for improve efficiency?

For example, external component for bq25710 (NVDC) , Roadmap for TI's HPBB, etc.

https://www.renesas.com/jp/ja/www/doc/datasheet/isl9241.pdf

Best regards,

Satoshi

  • 0
    TI__Mastermind 25800 points

    Hey Satoshi,

    We do not support that device. However, for an architecture similar to that, you are looking at improving the system efficiency rather than the charging efficiency.

    In that scenario, the BQ25710 supports a Pass Through Mode, to allow the input voltage to be directly passed to the system voltage side. This is the highest efficiency mode of the BQ25710 charging controller as the only losses suffers are DC conduction losses.

    I would recommend reviewing section 9.4.3 Pass Through Mode (PTM) the datasheet for more details on this mode. For an efficiency calculation, consider the I2R losses through the 2 HSFET Rdson's, the inductor DCR, and the 10mOhm RAC resistor.

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Guru 19645 points

    Joel-san

    Thank you for reply,

    About Pass Through Mode, is PTM operate only light load condition?

    Can bq25710 use PTM on High power condition? (For example, 50W, etc)

    Datasheet is described below;

    Best regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Mastermind 25800 points

    Hey Satoshi-san,

    The high power condition should be fine. Again, make note of the power loss elements in PTM, which are the input sense resistor (RAC), the two HSFETs, and the inductor. All of these devices will factor into the power loss seen at high current.

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Guru 19645 points

    Joel-san

    Thank you for reply,

    Please let me know about three points below I noticed;

    ①When change to PTM, should bq25710 disable charging?

    ②If ① is no, is there detailed application note for PTM?

      (It is better to available reference design for heavy load condition)

    ③Can bq25710 change PTM to NVDC (or NVDC to PTM) on dynamically (system operating)? 

    Best regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Mastermind 25800 points

    Hey Satoshi-san,

    1) Charge has to be disabled for PTM mode to operate. So yes, charging is disabled. 

    3) PTM enabled is controlled by the ILIM_HIZ pin being pulled low. In order to be changed back to NVDC, the ILIM_HIZ pin will need to be pulled back within an acceptable range (between 1.2-4.0V).

    Regards,

    Joel H