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TPS54910: Power Management using TPS54910 and BQ25180

Elias Bachaalany
Prodigy 40 points
Part Number: TPS54910
Other Parts Discussed in Thread: BQ25180, PTH04T241W

Hello,

We are using the TPS54910 to drive a heating element requiring a supply voltage of 2.4V and consumes up to 8A.

The TPS54910 is supplied directly from a a high discharge Li-ion Battery 3.7V /1000mAh, this battery is charged using a  BQ25180 through USB.

Knowing that the system output of the BQ25180 can only supply maximum of 2.5 A, we connected the buck converter to the Battery directly.

TPS54910 will be disabled in from the main controller in case the battery voltage is low.

Can you please advice if such setup is adequate or do you recommend other options.

We tried to simulate the configuration of the TPS54910 using the WEBENCH, it turned out that it is not supported, are their any other method to simulate the configuration?

Best Regards 

  • 0
    TI__Guru**** 151530 points

    Hi Elias,

    What will be the voltage range on your battery?  Usually, lithium batteries are charged up to ~4.2V and discharged down to 3V or lower.  With such a high power draw across the battery's internal impedance, there will likely be a lot of energy left in the battery if you only discharge it to 3V.  I don't think the 3V to 4V input range of the TPS54910 is sufficient.

    The PTH04T241W is a more integrated, easy to use power module with a wider input voltage range.  And we have some in stock.

    Finally, keep in mind that a standard USB port does not provide much power, your battery only holds ~3.7Whr of energy, and your load draws 19.2W.  You don't have enough power to run the heater at full power for very long.

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 40 points

    Hi Chris,

    Thank you for the feedback, in fact we were looking for a more cost effective solution.

    We are using USB C connection so we will be able to use a higher voltage for battery charging if required.

    The battery used is LPHD7425048 1000mAh 6A with voltage range between 2.75 and 4.2V

    the Heating Element draws 8A @2.4V  and it will be supplied for 8s only and this is for 10 times a day.

    Can you recommend a more cost effective solution form TI

    Elias

  • 0 in reply to Elias Bachaalany
    TI__Genius 14876 points

    Hello Elias,

    Chris is out for the day, he will be able to come back to you on Monday.

    Thanks a lot!


    Regards,
    Dorian

  • 0 in reply to Elias Bachaalany
    TI__Guru**** 151530 points

    Hi Elias,

    Thanks for explaining more about your system.

    I recommend checking with the battery charger people on a suitable charger for your needs.  BQ25180 is a linear charger and does not support higher voltage/power charging and it will get very hot when charging at higher currents.

    What volumes do you need and when do you plan to go to production?

    A power module integrates many components of your BOM (such as the power inductor, capacitors, resistors, etc.) so you will not incur the additional cost for each of these parts.  Also, the design effort is simplified.  Finally, we have stock of PTH04T241W right now.

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 40 points

    Hello Chris,

    Thank you for your feedback, will be checking with the Battery Charger support on a suitable charger.

    As for the buck converter, what about using the LM21212MHE, what would be the advantages/disadvantages of this chip versus the PTH04T241W Module.

    First batch will be 10K , production should be toward November 

    Best Regards

    Elias

  • +1 in reply to Elias Bachaalany
    TI__Guru**** 151530 points

    Thanks for checking with them.

    Yes, there is stock of the LM21212, but that one only operates down to 2.95Vin.  So, you will not be able to get all the energy out of the battery especially when you consider the voltage drop across its internal impedance.

    Chris

  • 0 in reply to Chris Glaser
    Prodigy 40 points

    Dear Chris,

    In fact we will not operate the battery below 3V so it seems the LM21212 is the adequate chip.Good to know that their are available stock from this unit.

    Thank you for your support

    Best 

    Elias