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Required Fuel Gauge for LTO Battery

narendra singh1
Prodigy 230 points
Other Parts Discussed in Thread: GPCCHEM, BQ27Z561, BQ27Z746, BQ40Z50

Hi,

We are in need of Fuel gauge or battery monitor for Lithium Titanate Oxide battery which minimum pack voltage is 1.9V and Max 2.7V for one of our application. We plan to use single cell. Does TI have any solution for this battery chemistry?

If not, is there any chip which can operate at less than 1.9V battery pack(may be for other chemistry as well)?

Or is there is chip which can support low battery pack voltage as low as 1.8 or 1.9V(Chip operating voltage can be higher for which we can use boost regulator).

We prefer to have I2C interface for the chip.

Regards

Narendra Singh

  • 0
    TI__Guru** 104525 points

    Hello Narendra,

    We do have some chem IDs which support this chemistry, I would recommend using our GPCCHEM tool to see if any of them match the battery you plan to use.

    The minimum operating voltage for our newest 1s gauges are 2v, so you will not be able to use the full voltage range of the cell, you would need to use a high cell count and a multicell gauge, or stop discharge above 2v. BQ27z746 and BQ27z561 are the newest 1s flash gauges I would recommend looking at. Or the BQ40Z50 for multicell.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 230 points

    Hi Wyatt,

    Thanks for your quick reply. I too had come across this BQ27z746  chip during my part search but was looking if any other solution as well which can support lower voltage. Looking at internal block diagram, this chip uses 1.8V internal regulator only for temperature cutoff sensing and doesn't use for gauging(i may be wrong on this). battery pack it can support up to 1.5V.  On this basis, i too thought this chip might be suitable however i am uncertain about chemistry it can support which i am yet to find and now will look using GPCCHEM tool as you suggest. i too agree for <2V, this chip may not function as expected and hence we may need to sacrifice the battery capacity.

    Regards

    Narendra SIngh

  • 0 in reply to narendra singh1
    TI__Guru** 104525 points

    Hello Narendra,

    The minimum supply voltage for BQ27Z746 is 2V, I would not want to go down to exactly 2V without some headroom so 2.1V would probably be safe, but you would be leaving LTO battery capacity on the table if you did this.

    Sincerely,

    Wyatt Keller