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Original question:

BQ78350-R1A: Differences between chip versions BQ78350-R1, BQ78350-R1A and BQ78350-R2.

BQ78350-R1A: BQ78350-R1A

Manjunatha Nagamma
Prodigy 140 points
Part Number: BQ78350-R1A
Other Parts Discussed in Thread: BQ78350, , BQ76940, BQ76200, TIDA-00792, BQ78350-R1

I am considering BQ78350-R1A along with BQ76940 and BQ76200 as a solution for Battery management of a 15 cell pack of LiFePo4 type battery. Does the BQ78350 support charging of this battery type? It is not clear to me whether I need external charger solution or if BQ78350 could take care of the charging. Please clarify.

  • 0
    TI__Genius 10830 points

    Hi Manjunatha,
    BQ78350-R1A is a monitor (check this video for more info about what a monitor is). It is not a charger.

    I am going to direct you to my colleagues in our battery charger group, in case they have a solution to suggest.

  • 0 in reply to David Hien
    TI__Genius 10240 points

    Hi Manjunatha,

    There is a DC-DC battery charger design https://www.ti.com/tool/PMP4308 as a reference. We don't have dedicated DC-DC charger IC above 7S. The charger IC can be searached at https://www.ti.com/power-management/battery-management/charger-ics/products.html.

  • 0 in reply to ezhao
    Prodigy 140 points

    Hi David, 

    Thanks for the suggestion. I came across this design TIDA-00792 which is a complete battery management solution for 15 cell Lithium phosphate battery. Do you see anything lacking in this reference design which I might have overlooked?

    Regards,

    Manjunatha

  • 0 in reply to Manjunatha Nagamma
    TI__Genius 10830 points

    Hi Manjunatha,
    Well, I have a very limited view of your requirements but based on what I saw, TIDA-00792 is indeed a suitable reference design for a 15s battery pack integrating a gauge, a 15s monitor, high-side FET driver...

  • 0 in reply to David Hien
    Prodigy 140 points

    Thanks David. I am looking for a monitor, charger and fuel gauge solution for the 15S pack. I found TIDA-00792 reference design most relevant for my requirements. However I am not convinced about the charging. The BQ78350 chip talks about charger functionality including support for CC/CV charging but based on your comment, I am not confident about my understanding this feature correctly. May be Eric can advise and give more clarity of the charging function mentioned in Chapter 5 of Technical reference document  SLUUC78. I like to know what feature is available and what is missing when it comes to charging functionality of BQ78350.

    Eric - Please advice.

    Regards,

    Manjunatha.

  • 0 in reply to Manjunatha Nagamma
    TI__Genius 10240 points

    Hi Manjunatha,

    We don't have dedicated battery charger IC above 7S. 

    BQ78350 is a gauge IC without charging function.

  • 0 in reply to ezhao
    Prodigy 140 points

    Hi Eric, 

    I understand the BQ78350 is not a dedicated charger. But I like to get clarifications on the below features mentioned in TI documentation and reference designs. Request you to explain the scope / limitation of these features as it pertains to charging feature supported in the device. Sorry for my limited understanding and thanks for your patience.

    1. The datasheet SLUSE05 has this mentioned under feature list - "Supports CC-CV charging, including precharge, inhibit and charge suspend".  

    2. The technical reference manual SLUUC78 section 5 refers to Charging algorithm supported by the device.

    3. The TIDA-00792 reference design shows BQ78350 controlling the High side MOSFET driver BQ76200 that controls FETs in charge / discharge / Pre-charge.  

    Regards,

    Manjunatha.

  • 0 in reply to Manjunatha Nagamma
    TI__Guru* 77283 points

    Hi Manjunatha,

    Many TI Battery gauges like the BQ78350 are designed to work with smart charger devices. Since the gauge has measurement data for cell voltage, current, and temperature, it can recommend charging voltage and current to a smart charging device to provide the safest charging for the battery. The BQ78350-R2 firmware (this firmware can be downloaded from ti.com and loaded to the BQ78350-R1 device) has even more charging parameters that can be used in this way. 

    The BQ78350 in combination with the BQ769x0 monitor also does control external FETs to stop charging or discharging in the event of a protection fault like over-voltage, under-voltage, over-current, or a temperature fault. There is also the ability to control a pre-charge FET - this allows the battery to charge slowly while at low voltage to protect the battery health. Once the voltage is high-enough, the charge FET can be enabled to allow fast charging.

    In summary, the TIDA-00792 solution provides gauging, monitoring, and protection (using FETs). The gauge also recommends charging conditions (voltage and current) to a smart charger based on temperature conditions of the cells. 

    I hope this helps. Best regards,

    Matt